Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “weighting”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Conspicuity of normal and pathologic female pelvic anatomy: comparison of gadolinium-enhanced T1-weighted images and fast spin echo T2-weighted images.

PURPOSE: Our goal was to compare the conspicuity of normal and pathologic female pelvic anatomy between gadolinium-enhanced T1-weighted images and fast SE (FSE) T2-weighted images. METHOD: In 48 consecutive female patients, pre- and postenhanced T1-weighted images were compared with FSE T2-weighted images acquired with a phased array coil. Normal zonal anatomy (ZA) and pathologic abnormalities in gadolinium-enhanced T1-weighted images were rated as increased, decreased, or without change in conspicuity as compared with FSE T2-weighted images. RESULTS: The normal ZA of the uterine corpus on T1-weighted images showed a decrease in conspicuity in 93% of patients and an increase in 7% compared with FSE T2-weighted images. Conspicuity of cervical ZA on T1-weighted images was decreased in 86%, increased in 6%, and without change in 8% as compared with FSE T2-weighted images. ZA of the vagina on T1-weighted images was decreased in 94% and increased in 6% as compared with FSE T2-weighted images. On T1-weighted images, ovarian anatomy delineation was decreased in 95% and increased in 5% as compared with FSE T2-weighted images. Conspicuity of malignant pathologic abnormalities on T1-weighted images was decreased in 81%, increased in 11%, and without change in 8% as compared with FSE T2-weighted images. In patients with benign disease, conspicuity on T1-weighted images was decreased in 92%, increased in none, and without change in 8% as compared with FSE T2-weighted images. The p value for all categories was < 0.0001. CONCLUSION: Conspicuity of both normal and pathologic anatomy was significantly decreased on enhanced T1-weighted images. The use of gadolinium cannot replace T2-weighted scans for delineation of anatomy and disease and should be reserved to cases in which standard imaging sequences are not sufficiently diagnostic.

Adolescent↗
PubMed2005

Intention to lose weight, weight changes, and 18-y mortality in overweight individuals without co-morbidities.

BACKGROUND: Weight loss in the obese improves risk factors for cardiovascular diseases and diabetes. However, several studies have shown inconsistent long-term effects of weight loss on mortality. We investigated the influence on mortality of intention to lose weight and subsequent weight changes among overweight individuals without known co-morbidities. METHODS AND FINDINGS: In 1975, a cohort of individuals reported height, weight, and current attempts (defined as "intention") to lose weight, and in 1981, they reported current weight. Mortality of the 2,957 participants with body mass index > or = 25 kg/m2 in 1975 and without pre-existing or current diseases was followed from 1982 through 1999, and 268 participants died. The association of intention to lose weight in 1975 and actual weight change until 1981 with mortality was analysed while controlling for behavioural and psychosocial risk factors and hypertension as possible confounders. Compared with the group not intending to lose and able to maintain stable weight, the hazard ratios (with 95% confidence intervals) in the group intending to lose weight were 0.84 (0.49-1.48) for those with stable weight, 1.86 (1.22-2.87) for those losing weight, and 0.93 (0.55-1.56) for those gaining weight. In the group not intending to lose weight, hazard ratios were 1.17 (0.82-1.66) for those who did lose weight, and 1.57 (1.08-2.30) for those gaining weight. CONCLUSION: Deliberate weight loss in overweight individuals without known co-morbidities may be hazardous in the long term. The health effects of weight loss are complex, possibly composed of oppositely acting processes, and need more research.

Adult↗
PubMed2000

[Maternal weight gain during pregnancy. Relation to prepregnancy weight].

OBJECTIVE: To describe the weight gain during normal pregnancy and to evaluate the relationship between maternal pregravid weight and gestational weight change. MATERIALS AND METHODS: The study population consisted of 1443 healthy women who delivered of singleton, live infants. Pregravid weight was determined on the basis of maternal reporting and categorized into four categories using the following BMI cut points (kg m-2): underweight (< 19.8), normal weight (19.8-26.0), overweight (26.1-29.0), obesity (> 29.0). Length of gestation was first determined from the onset of the last menstrual period. Weight gain by gestational age: the woman's pregravid weight was subtracted from the weight measured at each visit. Total weight gain was calculated from the last weight measured. RESULTS: The mean (+/- SD) total amounts of weight gained by gestational week were 0.9 +/- 0.7 kg by 12 weeks, 7.5 +/- 2.7 kg by 28 weeks, and 12.9 +/- 3.8 kg by 40 weeks. Weight gain curve for this sample of women was linear. Weight curves in groups of women who differed in prepregnancy weight status showed similar linear trends. Compared with normal-weight women, obese and overweight women gained less during pregnancy (13.3 kg vs 11.8 kg, 12.2 kg, respectively). CONCLUSIONS: Total weight gain in study population was similar to weight gain in other populations reported in publications. There was a tendency for overweight and obese women to gain weight at a lower rate, thus result in a overall lower total weight gain.

Adult↗
PubMed2003

Gestational weight gain and postpartum behaviors associated with weight change from early pregnancy to 1 y postpartum.

OBJECTIVES: (1) To describe the relative importance of gestational weight gain, postpartum exercise, food intake and breastfeeding to weight change from early pregnancy to 1 y postpartum; and (2) to identify subgroups of women at greatest risk for major weight gain surrounding childbearing. DESIGN: A prospective cohort study of women who registered for obstetrical care in a hospital and primary care clinic system serving a 10 county area of upstate New York. SUBJECTS: A total of 540 healthy adult women who gave birth to full-term singleton infants. MEASUREMENTS: Sociodemographic characteristics, exercise, food-related behaviors and breastfeeding were assessed using the medical record and a mailed questionnaire. Body weight was measured at prenatal visits and 1 y postpartum. Weight retained and major weight gain (4.55 kg) at 1 y postpartum were the main outcomes. ANALYSIS: Linear and logistic regression analyses were conducted. RESULTS: Women were on average 1.51+/-5.95 kg heavier at 1 y postpartum than they were in early pregnancy. Nearly 25% of women experienced a major weight gain of 4.55 kg or more at 1 y postpartum. Gestational weight gain, exercise frequency, change in food intake and breastfeeding were each significantly related to postpartum weight retention. With the exception of breastfeeding, all of these factors were also associated with major weight gain. Women under 20 y or over 40 y at delivery, and single women retained significantly more weight. Lower income women with gestational weight gains above the Institute of Medicine (IOM) range retained 3.73 kg more than lower income women who gained within the range. They were also 4.7 times more likely to experience major weight gain with childbearing. The impact of exceeding the IOM gestational weight gain guidelines was three times greater in lower income women than it was in higher income women. CONCLUSION: Gestational weight gain, postpartum exercise frequency, and food intake are significantly associated with weight change from early pregnancy to 1 y postpartum and major weight gain with childbearing. Lower income women who gain more weight in pregnancy than the IOM recommends are at high risk for major weight gain with childbearing.

Adult↗
PubMed2003

Patellofemoral kinematics during weight-bearing and non-weight-bearing knee extension in persons with lateral subluxation of the patella: a preliminary study.

STUDY DESIGN: Single-group, repeated-measures design. OBJECTIVE: To compare patellofemoral joint kinematics during weight-bearing and non-weight-bearing knee extension in persons with lateral subluxation of the patella. BACKGROUND: The only previous study to quantify differences in patellofemoral joint kinematics during weight-bearing and non-weight-bearing tasks was limited in that static loading conditions were utilized. Differences in patellofemoral joint kinematics between weight-bearing and non-weight-bearing conditions have not been quantified during dynamic movement. METHODS AND MEASURES: Six females with a diagnosis of patellofemoral pain and lateral subluxation of the patella participated. Using kinematic magnetic resonance imaging, axial images of the patellofemoral joint were obtained as subjects extended their knee from 45 degrees to 0 degrees during non-weight-bearing (5% body weight resistance) and weight-bearing (unilateral squat) conditions. Measurements of patellofemoral joint relationships (medial/lateral patellar displacement and patellar tilt), as well as femur and patella rotations relative to an external reference system (ie, the image field of view), were obtained at 3 degrees increments during knee extension. RESULTS: During non-weight-bearing knee extension, lateral patellar displacement was more pronounced than during the weight-bearing condition between 30 degrees and 12 degrees of knee extension, with statistical significance being reached at 27 degrees, 24 degrees, and 21 degrees. No differences in lateral patellar tilt were observed between conditions (P = .065). During the weight-bearing condition, internal femoral rotation was significantly greater than during the non-weight-bearing condition as the knee extended from 18 degrees to 0 degrees. During the non-weight-bearing condition, the amount of lateral patellar rotation was significantly greater than during the weight-bearing condition throughout the range of motion tested. CONCLUSIONS: The results of this study demonstrated that lateral patellar displacement was more pronounced during non-weight-bearing knee extension compared to weight-bearing knee extension in persons with lateral patellar subluxation. In addition, the results of this investigation suggest that the patellofemoral joint kinematics during non-weight-bearing could be characterized as the patella rotating on the femur, while the patellofemoral joint kinematics during the weight-bearing condition could be characterized as the femur rotating underneath the patella.

Adolescent↗
PubMed1999

Weight, weight change, mortality in a random sample of older community-dwelling women.

OBJECTIVE: To evaluate the relationship between measured weight, weight change, and 6-year mortality risk in a random sample of 648 community-dwelling women aged 65 and older from Baltimore, Maryland. MEASUREMENTS: Data were collected using a standardized questionnaire and administered in person by trained interviewers. Questionnaires were completed annually from 1984 to 1986, and body weight was measured at each interview. Weight was defined as body mass index (BMI) of low (< 23 kg/m2), average (> or = 23 kg/m2 to < or = 28 kg/m2), and high (> 28 kg/m2). Four mutually exclusive categories of weight change of at least 4.5% in BMI over the three annual interviews were developed to describe all possible weight change patterns: weight gain, weight loss, no change, and weight cycling. RESULTS: During the follow-up period, 106 women (16%) died. Women with low baseline BMI, regardless of weight change, and those who lost weight, regardless of baseline BMI had increased mortality risk. Women with average baseline BMI and weight loss had a very high mortality risk (hazard ratio (HR) 3.84, 95% Confidence interval (CI) 2.14-6.89). Women who weight cycled had increased mortality risk at low and high baseline weights, and a nonsignificant increased risk at average baseline weight (P = .069). Analyses were adjusted for age, education, smoking, alcohol usage, and pre-existing illness and included an interaction between weight change and baseline BMI. CONCLUSIONS: These results suggest that white, older, community-dwelling women are at an increased risk of mortality if they are underweight, lose weight, or weight cycle.

Aged↗
PubMed2004

Trying to lose weight, losing weight, and 9-year mortality in overweight U.S. adults with diabetes.

OBJECTIVE: The aim of this study was to examine the relationships between intention to lose weight, actual weight loss, and all-cause mortality among overweight individuals with diabetes. RESEARCH DESIGN AND METHODS: We performed a prospective analysis among 1,401 overweight diabetic adults aged > or =35 years sampled in the National Health Interview Survey. The previous year intention to lose weight and weight change were assessed by self-report. Nine-year mortality rates were examined according to intent to lose weight and weight loss, which were adjusted for age, sex, education, ethnicity, smoking, initial body weight, and diabetes complications. RESULTS: Individuals trying to lose weight had a 23% lower mortality rate (hazard rate ratio [HRR] 0.77, 95% CI 0.61-0.99) than those who reported not trying to lose weight. This association was as strong for those who failed to lose weight (0.72, 0.55-0.96) as for those who succeeded in losing weight (0.83, 0.63-1.08). Trying to lose weight was beneficial for overweight (BMI 25-30 kg/m2) individuals (0.62, 0.46-0.83) but not for obese (BMI>30) individuals (1.17, 0.72-1.92). Overall weight loss, without regard to intent, was associated with an increase of 22% (1.22, 0.99-1.50) in the mortality rate. This increase was largely explained by unintentional weight loss, which was associated with a 58% (1.58, 1.08-2.31) higher mortality rate. CONCLUSIONS: Overweight diabetic adults trying to lose weight have a reduced risk of all-cause mortality, independent of whether they lose weight. Actual weight loss is associated with increased mortality only if the weight loss is unintentional.

Adolescent↗
PubMed1996

Genetic (co)variances among birth weight, 200-day weight, and postweaning gain in composites and parental breeds of beef cattle.

Genetic and environmental (co)variances for birth weight, adjusted 200-d weight, and postweaning gain were estimated in nine parental and three composite populations of beef cattle. The parental breeds were Angus (A), Braunvieh (B), Charolais (C), Gelbvieh (G), Hereford (H), Limousin (L), Pinzgauer (P), Red Poll (R), and Simmental (S). The composites were MARC I (1/4 B, 1/4 C, 1/4 L, 1/8 H, 1/8 A), MARC II (1/4 G, 1/4 S, 1/4 H, 1/4 A), and MARC III (1/4 R, 1/4 P, 1/4 H, 1/4 A). Heritabilities of additive direct genetic effects for birth weight (.50) and postweaning gain (.49) were greater than for 200-d weight (.32). Heritabilities of additive maternal effects of .09 for birth weight and .10 for 200-d weight were much smaller than direct effect heritabilities. Heritabilities were larger in composites than in parental breeds for additive direct effects of all three traits but smaller for maternal 200-d weight. Correlations were high and positive for direct genetic effects of the three weight traits and higher in composites than in the parental breeds. Correlations between direct and maternal genetic effects for both birth weight and 200-d weight were near zero. Some differences in variances among populations were correlated with differences in weight and milk yield. Heavier populations had larger variances, supporting the use of logarithmic transformation of weights to stabilize variances among genetic groups. Increased average milk yield was correlated with decreased phenotypic variance of 200-d weight. Average milk yield was also implicated in the expression of direct and maternal genetic effects for 200-d weight and their covariance. Comparison of univariate and multivariate estimates of genetic variances suggested that it is important to include birth weight in multivariate analyses of all weight traits to account for increased preweaning mortality of calves with extremely heavy or light birth weights. Based on heritability estimates, within-herd selection in composites should be at least as effective as in purebreds. Some differences among populations in genetic parameters were indicated, especially maternal 200-d weight and its correlations with other traits.

Animals↗
PubMed1987

Can low birth weight after elevated maternal serum alpha-fetoprotein be explained by maternal weight?

Low birth weight infants are delivered with increased frequency in women who have elevated maternal serum alpha-fetoprotein values in the second trimester. Maternal serum alpha-fetoprotein elevations, however, are found more often in lighter-weight women, a group known to have lower-weight infants regardless of maternal serum alpha-fetoprotein levels. To clarify the association between elevated maternal serum alpha-fetoprotein levels and low birth weight independent of maternal weight, we applied a weight correction formula to maternal serum alpha-fetoprotein values from 9507 singleton viable pregnancies without major fetal malformations. Before adjusting for weight, 486 of the women (5.1%) had maternal serum alpha-fetoprotein values of 2.0 or more multiples of the median. The weight adjustment process removed 100 lighter-weight women from this category, added 58 heavier women, and led to an equivalent proportion of women in the various weight categories who were classified as having maternal serum alpha-fetoprotein values of 2.0 or more multiples of the median. Of the 388 low birth weight pregnancies (2500 g or less), 50 initially had maternal serum alpha-fetoprotein values of 2.0 or more multiples of the median; after weight adjustment, seven lighter-weight women were removed, four heavier women were added, the median birth weight fell from 2217 to 1956 g, and a threefold increase in risk was found for low birth weight outcome regardless of weight class. Maternal serum alpha-fetoprotein elevations predict increased risk for low birth weight outcome independent of maternal weight.

Birth Weight↗
PubMed1998

Hepatocellular carcinoma in North America: a multiinstitutional study of appearance on T1-weighted, T2-weighted, and serial gadolinium-enhanced gradient-echo images.

OBJECTIVE: The purpose of this study was to define the common appearances of hepatocellular carcinoma (HCC) in patients in North America by analyzing T1-weighted, T2-weighted, and serial gadolinium-enhanced gradient-echo images interpreted by radiologists at multiple institutions in North America. MATERIALS AND METHODS: One hundred thirteen consecutive patients with HCC from eight institutions were included in this retrospective case series. Inclusion criteria included MR imaging examinations performed on 1.5-T MR imagers using T1-weighted breath-hold spoiled gradient-echo images, T2-weighted images, and serial gadolinium-enhanced spoiled gradient-echo images. Diagnosis was established by histology in all patients. Images were analyzed retrospectively for lesion count, lesion diameter as less than or equal to 1.5 cm and greater than 1.5 cm, and signal intensity, by individual experienced radiologists at each institution. RESULTS: We found 354 HCC lesions in the 113 patients. Tumors were solitary in 63 patients, multifocal in 45 patients, and diffuse in five patients. Lesion appearance on combined T1-weighted, T2-weighted, and immediate gadolinium-enhanced spoiled gradient-echo images was as follows: 102 lesions (29%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited diffuse heterogeneous enhancement; 52 lesions (15%) were isointense on both T1- and T2-weighted images and exhibited diffuse homogeneous enhancement (all of these lesions measured < or = 1.5 cm in diameter); 50 lesions (14%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited diffuse homogeneous enhancement; 33 lesions (9%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited predominantly peripheral rim enhancement; and 27 lesions (8%) were hypointense on T1-weighted images, were isointense on T2-weighted images, and exhibited diffuse homogeneous enhancement. The remaining 90 lesions showed less common patterns. The appearance of HCCs greater than 1.5 cm and of HCCs less than or equal to 1.5 cm was significantly different (p = .001). The appearance of histologically proven HCCs is separately described. CONCLUSION: The combination of hypointensity on T1-weighted images, hyperintensity on T2-weighted images, and diffuse heterogeneous enhancement was the most common appearance of HCC on MR images in a multiinstitutional patient population in North America. Small HCCs measuring less than or equal to 1.5 cm were frequently isointense on both T1-weighted and T2-weighted images and may be detected on immediate gadolinium-enhanced images only as diffuse homogeneously enhancing lesions.

Adolescent↗
PubMed1994

Adolescents' perception of body weight and parents' weight for height status.

PURPOSE: To obtain data on the relationships between weight for height status, in adolescents and their parents, and adolescents' perceptions of body image and weight-loss behavior. METHODS: Weight and height were measured in both parents and adolescents from 213 families with an adolescent child aged 14-15 years who were participating in a community-based study of risk factors for coronary heart disease in Geelong, Australia. Information on adolescents' perceptions of body image, desired weight, and weight loss behaviors was obtained by questionnaire. RESULTS: Forty-one percent of the girls and 14% of the boys considered themselves overweight while 18% of both boys and girls were in this category on the basis of their body mass index (BMI). Most boys tended to see themselves as of normal weight while only girls below the 10th centile for BMI consistently rated themselves as normal. Adolescents who rated themselves as slim had parents whose BMI was significantly lower than that of the parents of adolescents who rated themselves as overweight. A significant proportion of adolescent girls (69%) and boys (27%) had at some time tried to lose weight. Female, but not male, adolescents of normal BMI who had tried to lose weight were themselves heavier and had significantly heavier mothers, but not fathers, than those in the normal range for BMI who had not attempted to do so. Adolescents who perceived an advantage in gaining weight had significantly shorter and lighter, but not leaner, fathers than those who perceived an advantage in losing weight. Only individuals below the 10th centile for BMI appeared to be content with their weight. On average the weight desired by girls and boys in the normal range for BMI was 6.6 and 2.0 kg less than their actual weight, while their desired height was 8.0 and 12.8 cm more than their actual height. CONCLUSIONS: The findings confirm gender differences in perceptions of and attitudes to body weight and body build. They also provide evidence for an association between adolescents perceptions of body weight and parents' weight for height status and suggest that the size of the "gap" between desired and actual weight is associated with the prevalence of weight-loss behavior.

Adolescent↗
PubMed1999

Long-term weight maintenance after an intensive weight-loss program.

OBJECTIVE: This prospective study assessed long-term weight maintenance of patients completing an intensive very-low-calorie diet (VLCD) weight-loss program. SUBJECTS: Individuals who had completed the 12-week core education program and lost > or = 10 kg were recruited. RESULTS: Of 154 eligible subjects, follow-up weights were obtained at > or = 2 years in 112 subjects (72.7%, 72 women, 40 men). Subjects had an average initial body mass index of 37.3 kg/m2 and an average weight loss of 29.7 kg in five months. Six hundred and forty-five follow-up weights (median, five per subject) were obtained over two to seven years of follow-up from clinic visits (70%) and self-report by telephone or mail (30%). Subjects regained an average of 2.5% per month of their lost weight during the first two to three years of follow-up; however, their weight stabilized over the next four years. Subjects regained an average of 73.4% of their weight loss during the first three years. The average weight loss maintained for 112 subjects was 22.8% of initial weight loss after an average of 5.3 years of follow-up. When successful weight maintenance was defined as maintaining a weight loss of 5% or 10% of initial (pre-treatment) body weight, 40% were maintaining a 5% weight loss at five years and 25% were maintaining a weight loss of 10% at 7 years. Multiple regression analyses suggested that age had a significant (p=0.004) and positive effect on weight maintenance. CONCLUSIONS: This study suggests that weight maintenance after an intensive VLCD program is improving but still needs intensive efforts to enable most individuals to maintain a substantial percentage of their weight loss long-term.

Adult↗
PubMed2000

Associations of weight change and weight variability with cardiovascular and all-cause mortality in the Chicago Western Electric Company Study.

Few studies of associations between weight loss or weight fluctuations and mortality have been sufficiently long term to permit exclusion of early deaths for a portion of follow-up long enough to eliminate likely effects of illness-related weight loss. This study examined associations of the variation (standard deviation and standard deviation about the trend (slope)) and trend (weight loss or weight gain) in body mass index (weight (kg)/height (m2) between 1958 and 1966 (minimum of five measurements) with subsequent 25-year mortality among 1,281 men originally aged 40-56 years from the Chicago Western Electric Company Study. In multivariate Cox regression models that included two slope variables representing weight loss and weight gain and each variability measure separately, weight loss and weight gain were significantly related to 15-year mortality but weight variability was not. Relative risks for cardiovascular disease mortality were 1.25 (95% confidence interval (CI): 1.09, 1.45) and 1.14 (95% CI: 0.97, 1.33), respectively, for weight loss and weight gain slopes larger by 0.12 kg/m2 per year; corresponding relative risks for all-cause mortality were 1.23 (95% CI: 1.10, 1.38) and 1.15 (95% CI: 1.03, 1.29), respectively. For follow-up years 16-25, none of these weight variables were significantly related to mortality. These results indicate that an association between weight loss and mortality may not persist beyond 15 years, and that weight variability may not be related to mortality independently of weight loss or weight gain.

Adult↗
PubMed1992

The effects of opioid blockade and GnRH administration upon luteinizing hormone secretion in patients with anorexia nervosa during the stages of weight loss and weight recovery.

OBJECTIVE: We examined the functional status of the hypothalamic-opioid system involved in LH secretion and the pituitary LH sensitivity and reserve in patients with anorexia nervosa were studied during body weight loss and weight recovery. We measured the temporal relationship between weight recovery, expression of hypothalamic-opioid activity and pituitary GnRH responsiveness, and resumption of ovulatory cycles. DESIGN: Five patients with anorexia nervosa were prospectively studied during weight loss and amenorrhoea, subsequently when they reached their ideal body weight but still remained amenorrhoeic and thereafter every 6 months until resumption of ovulatory cycles; one patient was studied only during weight loss, two during ideal body weight and amenorrhoea and one during ideal body weight and ovulatory cycles. Blood was sampled every 10 minutes over a 16-hour period on two alternate days. On study day 1 (control day), patients received two sets of saline infusion every 6 hours and one saline bolus at the beginning of the seventh hour; on study day 3 (experimental day), they received a saline infusion during the first 6 hours, an intravenous bolus of naloxone (20 mg) at the beginning of the seventh hour and then a continuous naloxone infusion (1.6 mg per hour) during the ensuing 6 hours. Pituitary LH sensitivity and reserve were assessed on both study days by the subsequent administration of 5 and 95 micrograms of GnRH 4 hours before the completion of each sampling period. Patients in ideal body weight and ovulatory cycles as well as five normal menstruating women included in the study for comparative purposes, were studied during the midluteal phase of a cycle. MEASUREMENTS: LH, oestradiol and progesterone were determined by radioimmunoassay. Areas under the LH curve were calculated by the trapezoid method; LH pulse detection was carried out by the program Cluster. RESULTS: Naloxone administration to patients with anorexia nervosa in the weight loss phase, did not significantly modify their serum LH levels nor the characteristics of its pulsatile secretion. Administration of the opioid blocker induced a significant increase in serum LH concentrations only in those patients in ideal body weight and amenorrhoea who resumed ovulatory cycles within the 6 months following the last study as well as in patients with an ideal body weight and ovulatory cycles and in normal controls. All patients and subjects who responded to naloxone administration exhibited significant increases in the area under the LH curve, mean LH pulse amplitude and peak area. Patients in ideal body weight and amenorrhoea who did not resume ovulatory cycles within the 6 months following the study days, did not respond to naloxone administration. There were no significant correlations between the magnitude of LH response to naloxone administration and the baseline levels of serum oestradiol and progesterone. All patients exhibited significant pituitary LH responses to both GnRH doses, regardless of the stage of the disease; however, the pituitary responsiveness shown by patients in ideal body weight was significantly higher than that presented by patients in weight loss. There were no significant differences between the responses to GnRH exhibited by patients in ideal body weight and amenorrhoea who responded to naloxone administration and those shown by patients in the same clinical condition but who were insensitive to opioid blockade. CONCLUSIONS: The re-establishment of hypothalamic-opioid inhibitory activity involved in LH secretion in patients with anorexia nervosa during the phase of weight gain predicts imminent restoration of ovulatory cycles. Pituitary LH response to exogenous GnRH during weight recovery does not accurately predict the outcome of the disease regarding reinitiation of menstrual cycles; however, it might be an indicator that the normal function of the hypothalamic-pituitary axis is being restored.

Adolescent↗
PubMed2006

Underestimation and overestimation of personal weight status: associations with socio-demographic characteristics and weight maintenance intentions.

OBJECTIVE: Unwarranted underestimation and overestimation of personal weight status may prevent weight maintenance behaviour. The present study reports on correlates of under- and overestimation of personal weight status and the association with weight maintenance intentions and self-reported action. DESIGN: Comparison of three cross-sectional surveys, representing different population groups. SUBJECTS: Survey 1: 1694 adolescents 13-19 years of age; survey 2: 979 nonobese adults 25-35 years of age; survey 3: 617 adults 21-62 years of age. MEASUREMENTS: Self-administered written questionnaires (surveys 1 and 3) and telephone-administered questionnaires (survey 2); self-reported BMI, self-rated weight status, intentions and self-reported actions to avoid weight gain or to lose weight, sex, age, education and ethnic background. Respondents were classified as people who are realistic about personal body weight status or people who under- and overestimate their body weight status, based on BMI and self-rated weight status. RESULTS: Most respondents in the three survey populations were realistic about their weight status. Overestimation of weight status was consistently more likely among women, whereas underestimation was more likely among men, older respondents and respondents from ethnic minorities. Self-rated weight status was a stronger correlate of intentions and self-report actions to avoid weight gain than weight status based on Body Mass Index. CONCLUSIONS: Relevant proportions of the study populations underestimated or overestimated their bodyweight status. Overestimation of personal weight status may lead to unwarranted weight maintenance actions, whereas underestimation may result in lack of motivation to avoid further weight gain.

Adolescent↗
PubMed2003

Leisure-time activity is an important determinant of long-term weight maintenance after weight loss in the Sibutramine Trial on Obesity Reduction and Maintenance (STORM trial).

BACKGROUND: The success rate of long-term maintenance of weight loss in obese patients is usually low. To improve the success rate, determinants of long-term weight maintenance must be identified. OBJECTIVE: The objective of the study was to identify determinants of long-term success in weight maintenance in obese subjects who completed the Sibutramine Trial on Obesity Reduction and Maintenance (n = 261), a multicenter European study of weight loss and weight maintenance in obesity that combines sibutramine treatment with dietary restriction and advice on exercise and behavior. DESIGN: We studied weight maintenance over 18 mo in subjects who had completed a 6-mo weight-loss phase. Factors included in the analysis were initial body weight, the percentage of initial body weight lost, dietary intake, various components of physical activity (measured with the Baecke questionnaire), the type of treatment (sibutramine or placebo), age, and sex. RESULTS: Multiple regression analysis identified treatment group (sibutramine or placebo), the percentage of the initial body weight that was lost during the 6-mo weight-loss phase, and the leisure-time physical activity index as significant determinants of weight maintenance. Together, these 3 factors explained 20% of the variation in weight maintenance (P < 0.001). Dietary factors, age, and sex were not significant predictors of weight-maintenance success in this study. CONCLUSIONS: Weight-maintenance success after weight loss is positively influenced by sibutramine treatment during weight maintenance, by a greater initial weight loss, and by a higher leisure-time physical activity index, which reflects higher levels of activities such as walking and cycling and lower levels of television viewing.

Adolescent↗
PubMed2006

Prevalence of overweight misperception and weight control behaviors among normal weight adolescents in the United States.

Weight perceptions and weight control behaviors have been documented with underweight and overweight adolescents, yet limited information is available on normal weight adolescents. This study investigates the prevalence of overweight misperceptions and weight control behaviors among normal weight adolescents in the U.S. by sociodemographic and geographic characteristics. We examined data from the 2003 Youth Risk Behavior Survey (YRBS). A total of 9,714 normal weight U.S. high school students were included in this study. Outcome measures included self-reported height and weight measurements, overweight misperceptions, and weight control behaviors. Weighted prevalence estimates and odds ratios were computed. There were 16.2% of normal weight students who perceived themselves as overweight. Females (25.3%) were more likely to perceive themselves as overweight than males (6.7%) (p < 0.05). Misperceptions of overweight were highest among white (18.3%) and Hispanic students (15.2%) and lowest among black students (5.8%). Females (16.8%) outnumbered males (6.8%) in practicing at least one unhealthy weight control behavior (use of diet pills, laxatives, and fasting) in the past 30 days. The percentage of students who practiced at least one weight control behavior was similar by ethnicity. There were no significant differences in overweight misperception and weight control behaviors by grade level, geographic region, or metropolitan status. A significant portion of normal weight adolescents misperceive themselves as overweight and are engaging in unhealthy weight control behaviors. These data suggest that obesity prevention programs should address weight misperceptions and the harmful effects of unhealthy weight control methods even among normal weight adolescents.

Adolescent↗
PubMed1989

The weight loss profile: a biopsychosocial approach to weight loss.

Obesity is a common complicating condition in a variety of medical problems. Often effective consultation liaison involves recommendations to overweight patients involving lifestyle and health risk modification. Factors that need to be addressed include exercise, nutritional counseling/caloric restriction, and attitude and behavioral change regarding eating. Patients requiring weight loss typically seek various commercial programs that are readily accessible. One major problem associated with such programs is the high attrition rate within the first six weeks of initiation. Therefore, attempts to facilitate longer-term retention and associated weight loss are warranted. One approach is the identification of factors associated with problems in short-term retention and weight loss followed by the implementation of brief interventions to potentially reverse the influence of these factors on retention and weight loss. The present investigation was conducted to determine the effects of such a strategy on short-term retention and weight loss in a commercial weight loss program. Two groups (n = 66 per group) of female participants with a mean age of thirty-eight years, mean initial weight of 184.6 lbs, mean height of 64.3 inches, mean goal weight of 147.3 lbs, mean Body Mass Index of 31.4 kg/m2 were recruited for the study. Groups were matched for age, initial weight, height, goal weight, and body mass index. One group (controls) received a standard thirteen-week group cognitive-behavioral intervention that emphasized the teaching of self-management strategies for weight reduction. The second group (personalized intervention) received the same thirteen-week cognitive-behavioral intervention. This group also completed a questionnaire (Weight Loss Profile) that identifies factors associated with poor retention and minimal weight loss. Targeted interventions were implemented to modify specific problem areas identified on the Weight Loss Profile. The problem areas were based upon previous research which identified predictors of retention and weight loss. The problem areas included job stress, social comfort, self-consciousness regarding weight and eating behaviors, concern with physical appearance, Type A behavior pattern, social support, motivation, and expectation of success. Both groups also received 1,000 calorie/day prepackaged foods, instruction in mild exercise, and nutritional counseling. Weekly weights and attendance were recorded across the thirteen consecutive week period. The group receiving the personalized intervention lost significantly more weight than the control group (30 lbs vs. 11 lbs, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗