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Biomedical subjects

Bonny L Specker

Publications and source records attributed to Bonny L Specker.

9 recordsLinked to original sources
PubMed2006

Influence of parents' eating behaviors and child feeding practices on children's weight status.

OBJECTIVE: To investigate the effects of mothers' and fathers' eating behaviors, child feeding practices, and BMI on percentage body fat and BMI in their children. RESEARCH METHODS AND PROCEDURES: Four hundred fifty-eight parents (239 mothers, 219 fathers) were asked to complete two questionnaires: the Three-Factor Eating Questionnaire and the Child Feeding Questionnaire, which measure dimensions of parent eating behavior and child feeding practices, respectively. Parent BMI was calculated from self-reported height and weight; children's measures included BMI and percentage fat assessed by DXA. Regression analyses were used to analyze relationships between parents' BMI and questionnaire scores and children's weight status. RESULTS: One hundred forty-three mothers and 68 fathers returned questionnaires, representing parents of 148 children 3 to 5 years old (78 boys). Children's weight was related to mothers' BMI, but not fathers'. Girls had a greater BMI if either parent reported being overweight as a child, and both girls and boys were likely to be overweight if their mothers believed they had risky eating habits (fussiness, eating too much, etc.). Girls with fathers who were more controlling had a higher percentage fat; these fathers were also more concerned about their daughters' future health. DISCUSSION: Mothers exert a strong influence over their children's weight and seem to be more concerned about their children's eating behaviors; however, fathers play a role in imposing child feeding practices. Gender bias may be present in child feeding, as suggested by dissimilar effects of parent practices on the weight status of girls vs. boys. Fathers should be included in future studies analyzing parent feeding practices and children's weight outcome.

Body Mass Index↗
PubMed2006

Fat mass gain is lower in calcium-supplemented than in unsupplemented preschool children with low dietary calcium intakes.

BACKGROUND: Dietary calcium may play a role in the stimulation of lipolysis and the inhibition of lipogenesis, thereby reducing body fat. OBJECTIVE: The aim was to determine whether an association existed between change in percentage body fat (%BF) or fat mass and calcium intake in children aged 3-5 y. DESIGN: A secondary analysis of a 1-y randomized calcium and activity trial in 178 children was conducted. Three-day diet records and 48-h accelerometer readings were obtained at 0, 6, and 12 mo. Body composition was measured by dual-energy X-ray absorptiometry at 0 and 12 mo. RESULTS: The decrease in %BF was less in girls (-0.6 +/- 2.8%) than in boys (-1.5 +/- 2.6%; P = 0.03) and correlated with age (r = 0.19, P = 0.01) and maternal body mass index (r = 0.19, P = 0.02). Changes in fat mass were not significantly different by activity group or between children randomly assigned to receive calcium or placebo (0.5 +/- 0.9 and 0.6 +/- 0.8 kg, respectively; P = 0.32). Similar findings were observed for the change in %BF. No correlations between %BF and fat mass changes and dietary calcium (r = -0.01, P = 0.9 and r = -0.05, P = 0.5) or total (dietary + supplement) calcium intake (r = -0.02, P = 0.8 and r = -0.06, P = 0.4) were observed. Among children in the lowest tertile of dietary calcium (<821 mg/d), fat mass gain was lower in the calcium group (0.3 +/- 0.5 kg) than in the placebo group (0.8 +/- 1.1 kg) (P = 0.04) but was not correlated with mean total calcium intake (r = -0.20). CONCLUSION: These findings support a weak relation between changes in fat mass gain and calcium intake in preschool children, who typically consume below recommended amounts of dietary calcium.

Absorptiometry, Photon↗
PubMed2005

Effect of protein supplementation during a 6-month strength and conditioning program on areal and volumetric bone parameters.

BACKGROUND: Skeletal loading and proper nutrition are necessary for optimal bone health. The appropriate amount of dietary protein to maximize skeletal health, however, is under constant debate. OBJECTIVE: To determine if 6 months of protein supplementation in conjunction with a strength and conditioning training program improves areal and volumetric bone mineral density (BMD). DESIGN: Fifty-two apparently healthy males and females ages 18-25 years were randomized to protein supplement (PRO, Myoplex, EAS, Inc. Golden CO) containing 280 kcal, 42 g protein, 21 g carbohydrate, and 1.5 g fat) or calorically equivalent carbohydrate control (CS). All subjects participated in a 5 sessions/week strength and conditioning program. Volumetric and areal BMD measurements were made by peripheral quantitative computed tomography (pQCT) of the tibia and whole body DXA. pSSI a measure of torsional bone strength, based on structural and material properties was obtained by pQCT. RESULTS: Measurements at the 20% tibia by pQCT revealed that overall there were significant increases in cortical vBMD (4.3 +/- 1.3 mg/cm(3)), cortical area (1.9 +/- 0.6 cm(2)), cortical thickness (0.05 +/- 0.02 mm) and pSSI (67 +/- 24 mm(3)), and a decrease in endosteal circumference (- 0.5 +/- 0.2 mm) over the intervention period (all, P < 0.05). None of the changes in DXA measures were found to differ by group or sex, there was a trend for a greater increase in whole body BMC among the carbohydrate compared to protein supplemented group and a greater increase among males (16 +/- 8 g) compared to females (-9 +/- 9 g) (P = 0.06). CONCLUSIONS: The results of this study indicate that the consumption of additional protein does not improve measurements of vBMD or bone size during a 6-month strength and conditioning program. Longer duration studies may be necessary to determine the influence of increased dietary protein on bone in young adults. Males and females may have different bone responses to increased protein intake while participating in a strength and conditioning program.

Absorptiometry, Photon↗
PubMed2005

Effect of protein supplementation during a 6-mo strength and conditioning program on insulin-like growth factor I and markers of bone turnover in young adults.

BACKGROUND: Exercise is beneficial for bone when adequate nutrition is provided. The role of protein consumption in bone health, however, is controversial. OBJECTIVE: The objective was to ascertain the effect of high protein intake on insulin-like growth factor I (IGF-I) and markers of bone turnover during 6 mo of exercise training. DESIGN: Fifty-one subjects aged 18-25 y (28 men, 23 women) received a protein supplement (42 g protein, 24 g carbohydrate, 2 g fat) or a carbohydrate supplement (70 g carbohydrate) twice daily. Exercise consisted of alternating resistance training and running 5 times/wk. Plasma concentrations of IGF-I, insulin-like growth factor-binding protein 3, serum bone alkaline phosphatase, and urinary N-telopeptide collagen crosslink (NTx) concentrations were measured at 0, 3, and 6 mo after 24 h without exercise and a 12-h fast. RESULTS: Three-day diet records indicated no difference in energy intake between the groups. Average protein intakes after supplementation began in the protein and carbohydrate groups were 2.2 +/- 0.1 and 1.1 +/- 0.1 g/kg, respectively (P < 0.001). The increase in plasma IGF-I was greater in the protein group than in the carbohydrate group (time x supplement interaction, P = 0.01). There were no significant changes over time or significant differences by supplement in plasma insulin-like growth factor-binding protein 3 (44 and 40 kDa). Serum bone alkaline phosphatase increased significantly over time (P = 0.04) and tended to be higher in the protein group than in the carbohydrate group (P = 0.06). NTx concentrations changed over time (time and time squared; P < 0.01 for both) and were greater in the protein group than in the carbohydrate group (P = 0.04). Men had higher NTx concentrations than did women (74.6 +/- 3.4 and 60.0 +/- 3.8 nmol/mmol creatinine; P = 0.005). CONCLUSION: Protein supplementation during a strength and conditioning program resulted in changes in IGF-I concentrations.

Adolescent↗
PubMed2004

Relationships between bone mass and circulating leptin concentrations in Hutterites.

A limited number of previous studies have shown inverse associations between bone mass or density and circulating leptin in humans. Relationships between bone mass and circulating leptin in Hutterites, who have elevated bone density, are unknown. Knowledge gained from studies in mice suggests that Hutterites exhibit traits consistent with a deficiency in circulating leptin or in leptin signaling. We examined relationships between whole body (WB) and regional (lumbar, total hip, femoral neck, trochanter) bone mineral content (BMC) by dual energy X-ray absorptiometry and circulating leptin in 249 Hutterites (137 female) ages 20-55 years and 72 similarly aged non-Hutterites (37 female). We tested the hypothesis that (1) Hutterites will have low circulating leptin concentrations for a given amount of body fat compared to non-Hutterites, and (2) controlling for body fat, there will be an inverse relationship between BMC and circulating leptin among Hutterites. Hutterites had higher BMC than non-Hutterites at all skeletal sites after adjusting for site-specific bone area, age, and sex (P </= 0.02). Hutterite females had higher leptin concentrations than non-Hutterite females [geometric mean and 95% confidence interval (CI): 18.38 (17.18, 19.67) vs. 14.30 (12.55, 16.28), P </= 0.001) after adjusting for WB fat mass. Hutterite males also had higher leptin concentrations than non-Hutterite males [geometric mean and 95% CI: 6.53 (6.11, 6.98) vs. 5.62 (4.98, 6.35), P = 0.03) after adjusting for WB fat mass. We used backward stepwise regression to determine significant (P </= 0.10) covariates to include in models predicting WB and regional BMC among Hutterites (separately by sex). Subsequently, we entered leptin (log-transformed) to models to test for significance (P </= 0.05). After adjusting for covariates, leptin concentration was not a significant predictor of BMC at any site, in either sex, among Hutterites. It is possible that genetic influences that interfere with hypothalamic leptin signaling, in a manner unrelated to adipocyte leptin production, contribute to elevated Hutterite bone density.

Adult↗
PubMed2002

Bone mineral changes during pregnancy and lactation.

Significant calcium transfer from the mother to the fetus and infant occurs during pregnancy and lactation, theoretically placing the mother at an increased risk for osteoporosis later in life. During pregnancy, intestinal calcium absorption increases to meet much of the fetal calcium needs. Maternal bone loss also may occur in the last months of pregnancy, a time when the fetal skeleton is rapidly mineralizing. The calcium needed for breast milk production is met through renal calcium conservation and, to a greater extent, by mobilization of calcium from the maternal skeleton. Women experience a transient loss of approx 3-7% of their bone density during lactation, which is rapidly regained after weaning. The rate and extent of recovery are influenced by the duration of lactation and postpartum amenorrhea and differ by skeletal site. Additional calcium intake does not prevent bone loss during lactation or enhance the recovery after weaning. The recovery of bone is complete for most women and occurs even with shortly spaced pregnancies. Epidemiologic studies have found that pregnancy and lactation are not associated with an increased risk of osteoporotic fractures.

Adaptation, Physiological↗
PubMed2002

Centile curves for bone densitometry measurements in healthy males and females ages 5-22 yr.

Normative pediatric bone measurement data are necessary for defining osteopenia in children and for identifying factors associated with normal bone growth. The LMS statistical method is used to produce centile curves plotting a growth characteristic as a function of age. The purpose of this study was to provide centile curves of bone measurements using peripheral quantitative computed tomography (pQCT) and dual X-ray absorptiometry (DXA) in 231 (107 male) healthy individuals ages 5 22 yr using the LMS method. pQCT (Norland XCT 2000; Norland, Ft. Atkinson, WI) was used to image a single slice at the 20% distal tibia. Periosteal circumference, endosteal circumference, and cortical density measurements were used to obtain centile curves. Whole-body DXA (Hologic QDR 4500; Hologic, Bedford, MA) was obtained and scans were analyzed using adult whole-body software for total body bone mineral content (BMC) and total body bone area. pQCT measurements showed prepubertal expansion of the tibia that plateaued in females at age 14 and continued in males until age 18. Tibia cortical density increased during the age of puberty more gradually in females than in males. DXA measurement curves showed that total body BMC and total body bone area plateaued in females at approximately age 15, whereas male curves of the same measurements showed a continued increase.

Adolescent↗