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PubMed2003

Longitudinal driving performance in early-stage dementia of the Alzheimer type.

OBJECTIVES: To longitudinally assess on-road driving performance in healthy older adults and those with early-stage dementia of the Alzheimer type (DAT). DESIGN: A prospective longitudinal study. SETTING: Large urban medical center and surrounding area. PARTICIPANTS: A sample of 58 healthy controls, 21 participants with very mild DAT, and 29 participants with mild DAT participated. DAT was diagnosed using validated clinical diagnostic criteria and staged according to the Clinical Dementia Rating (CDR) Scale. MEASUREMENTS: Healthy controls and individuals with very mild DAT and mild DAT were administered a standardized on-road driving assessment over repeated times of testing. RESULTS: Subjects in the CDR=1 group (mild DAT) had a faster rate of receiving a rating of not safe on the driving test than subjects in the CDR=0 group (healthy controls; log rank test, P=.006), and the survival function of the CDR=0.5 group (very mild DAT) fell between those of the CDR=0 and CDR=1 groups. A Cox proportional hazards model indicated a significant difference in survival functions between the CDR=0 and CDR=1 groups after baseline age was controlled for (P<.001). Cox regression analysis also indicated that baseline age was a significant risk factor for a rating of "not safe" (P=.002). CONCLUSION: This study provides longitudinal evidence for a decline in driving performance over time, primarily in early-stage DAT, and supports the need not only for driving assessments, but also for reevaluation of individuals with very mild and mild DAT.

Aged↗
PubMed2003

Longitudinal thrombopoietin plasma concentrations in fetuses with alloimmune thrombocytopenia treated with intrauterine PLT transfusions.

BACKGROUND: The purpose of this study was to describe longitudinal thrombopoietin (TPO) plasma concentrations in fetuses with fetomaternal alloimmune thrombocytopenia (FMAIT). STUDY DESIGN AND METHODS: Group 1 was the control group, 8 fetuses with normal hematopoiesis. Group 2 consisted of 4 nonthrombocytopenic fetuses with fetomaternal human PLT antigen incompatibility. Group 3 consisted of 14 fetuses with prenatal-diagnosed severe FMAIT owing to human PLT antigen-1a incompatibility. Fetal PLT counts, MoAb-specific immobilization of PLT antigen score, and TPO plasma concentrations were measured in a total number of 94 serial samples taken by cordocentesis before intrauterine PLT transfusion. RESULTS: Normal fetal TPO plasma concentrations ranged between 15 and 119 pg per mL (Group 1 median, 67 pg/mL). In fetuses with risk of FMAIT but normal PLT counts, TPO concentrations were normal (Group 2 median, 72 pg/mL; range, <15-158 pg/mL). In FMAIT with thrombocytopenia, the median TPO concentration was significantly higher than in Groups 1 and 2 (Group 3 median, 172 pg/mL; range, 15-623 pg/mL; p < 0.001). In the longitudinal analysis, TPO concentrations remained constant (n = 8), peaked only transiently (n = 3), or increased at the end of gestation (n = 3). Elevated TPO concentrations (592 and 623 pg/mL) were detected in one patient, who already had intracranial hemorrhage in utero. CONCLUSION: TPO concentrations are normal or slightly elevated in FMAIT. Further clinical information can be provided by the longitudinal analysis of TPO concentrations in severe FMAIT.

Antigens, Human Platelet↗
PubMed2001

The Ser(447)-Stop polymorphism of lipoprotein lipase is associated with variation in longitudinal serum high-density lipoprotein-cholesterol profiles: the Bogalusa Heart Study.

The Ser(447)-Stop polymorphism of lipoprotein lipase (LPL) has been associated with altered high-density lipoprotein-cholesterol (HDL-C) and triglyceride (TG) levels at individual measurements, but nothing is known of its associations with lipid profiles derived from serial measurements. We used multilevel statistical models to study effects of this polymorphism on longitudinal lipid profiles in 1,006 Bogalusa Heart Study subjects examined 4 to 9 times between the ages of 4 and 38 years. Stop(447) allele frequencies in African Americans (0.053 +/- 0.011) and whites (0.091 +/- 0.009) differed significantly (chi(2) = 7.595, 1 df, P =.006; Stop(447) homozygotes and heterozygotes combined). Overall, TG levels were lower and HDL-C levels higher in blacks than in whites of the same age and sex. Longitudinal TG profiles were lower in Stop(447) carriers at all ages. However, longitudinal HDL-C profiles differed among genotype groups with age: the Stop(447) allele was associated with higher HDL-C only in subjects above approximately 10 years of age. Genotype-specific HDL-C profiles also differed significantly among race/sex groups. Thus, we found evidence of LPL genotype effects that vary within individuals with age. Possible mechanisms, which could account for age-related changes in the effects of LPL variants, are discussed.

Adolescent↗
PubMed2002

Decline in muscle mass with age in women: a longitudinal study using an indirect measure.

Muscle mass is known to decline with age, but only limited longitudinal data exist to quantify the rate of loss. Using 24-hour urine creatinine, corrected for the contribution of dietary meat intake, we assessed the change with age prospectively in 107 women who provided a minimum of 3 sets of measurements spanning an average interval of 11.9 years, centered around age 55 years. The rate of change in 24-hour urine creatinine at that age averaged -0.94%/yr (95% confidence interval [CI], -1.24% to -0.64%/yr; P <.001). Change in creatinine excretion was directly correlated with change in weight (P <.01), with those gaining weight tending to gain both lean and fat mass. The rate of change in creatinine excretion with age in our subjects is similar to that described in published cross-sectional studies on age-related change in total body potassium and in longitudinal studies using (40)K and dual-energy xray absorptiometry. Our study is the largest longitudinal study reported to date and provides, perhaps, a more secure basis for estimating muscle mass change with age than has been available heretofore.

Adult↗
PubMed2000

[Methodological problems of longitudinal studies on schizophrenia].

Longitudinal studies are a key to understanding schizophrenia. They are the more informative, the longer the periods covered. Hence, good studies into the course of schizophrenia almost exclusively involve a lot of effort and cost. In practice, however, time-consuming methods and design variables must be avoided. The pitfalls this constraint produces are instructive of the difficulties longitudinal studies are faced with in striving for valid results. For reasons of research economy, requirements must be adjusted to study objectives. Studies into the short term course are less time-consuming, but because of the rapid changes in the illness course study intervals should be defined clearly and observed strictly. In long-term studies, too, one source of error lies in the highly varying lengths of illness of the patients studied. Even some of the classic long-term studies are marred by this error. The beginning of the follow-up period should be comparable across the study cohort and as close to illness onset as possible. To obtain generally valid results the probands must be representative of all the illness cases in the general population not only at the outset, but also all the later stages of the study. Besides the efforts to avoid attrition in the study cohort, ways must be found for correcting and estimating data for an acceptable proportion of drop-outs. In the analysis of course and outcome the indicators chosen must be apt to the traditional subtypes as well as to a theoretical symptom patterns and empirical symptom structures. In the context of typical design variables of longitudinal studies the assets and weaknesses of two retrospective and one prospective design will be discussed. Concerning the social course, importance of disease-independent factors, such as age, sex and level of social development at illness onset, as well as of control groups will be demonstrated. Predictor models will be discussed with reference to the direct and indirect influences involved. Examples of such analyses will be given.

Humans↗
PubMed2004

Longitudinal changes in plasma glucose values of the 75-g glucose tolerance test in triplet pregnancies.

We evaluated longitudinal changing patterns of 75 g glucose tolerance test (GTT) in triplet pregnancies. Eight triplet pregnancies were prospectively studied. All triplet pregnancies were fertilized with artificial reproductive techniques; patients showed no glucosuria or fasting hyperglycemia > 100 mg/dL before pregnancy. The 75-g GTT was performed at first, second, and third trimester, as well as at postpartum. Longitudinal changes in glucose levels at fasting, 1 hour, and 2 hours were compared by one-way repeated-measure analysis of variance (ANOVA) and Bonferroni/Dunn test ( p < 0.05). Values were expressed as mean +/- standard deviation. Each of the 3-point values of 75-g GTT decreased after 28 weeks of gestation in triplet pregnancies. During the third trimester, fasting values were significantly decreased compared with postpartum values (65.5 +/- 13.4 versus 74.6 +/- 4.0 mg/dL), and 2-hour values were significantly decreased from those of second-trimester 75-g GTT (116.3 +/- 19.5 versus 99.6 +/- 17.1 mg/dL). Longitudinal glucose values of 75-g GTT improve during third trimester in triplet pregnancies, suggesting that fetoplacental fuel drain may counterbalance maternal insulin resistance.

Adult↗
PubMedDate not supplied

[Longitudinal physical development of healthy children 0 to 18 years of age. Body length/height, body weight and growth velocity].

In addition to the Dortmunder longitudinal growth study we investigated development of height, weight and height velocity in 213 healthy boys and girls 15-18 years old. Number of children decreased in the age group of 17 and 18 years old to 143. The study was performed in a longitudinal way, the measurements were taken in an one year distance. The median height gain in boys between 15 and 18 years amounted to 9.3 cm, in girls to 2.1 cm, respectively. 18 years old boys are 180.1 cm tall, girls 167.9 cm. The median increment of body weight in boys from 15-18 years amounted to 7.3 kg, in girls 4.4 kg, respectively. Median weight in 18 years old boys amounted to 65.2 kg, in girls to 58.0 kg. International comparison with other longitudinal growth studies shows a trend of somewhat higher weight, height and height velocity of the children from our study.

Adolescent↗
PubMed1997

The Amsterdam Growth and Health Longitudinal Study. The past (1976-1996) and future (1997-?).

This article presents an overview of the Amsterdam Growth and Health Longitudinal Study (AGAHLS). This study was started in the 1970s, following a whole sample of 500 healthy 13-year-old boys and girls from two secondary schools. During the school period (12-17 years) annual measurements were performed with respect to anthropometrics, physiological and psychological parameters, lifestyle characteristics (activity, diet, smoking) and health parameters. A multiple longitudinal design was applied with overlapping birth cohorts and a cross-sectional measured control group to monitor for confounding factors such as time of measurement, cohort, dropout and testing effects. Emphasis is also placed on measures that enhance adherence of the subjects. The follow-up was extended with repeated measurements at age 21, 26 and 28. This enabled us to analyze the data with respect to tracking characteristics of biological and lifestyle variables over a period of 15 years between adolescence and adulthood and also to investigate quasi-causal relationships between the effects of a healthy lifestyle and indicators for cardiovascular diseases (CVD). Also new methods such as measurement of atherosclerosis and osteoporosis will be added and related to longitudinal measurements of the same subjects in the past. The main results that were obtained in the past are summarized and research questions for the near future are explained.

Adolescent↗
PubMed1999

Dental status of women in a 24-year longitudinal and cross-sectional study. Results from a population study of women in Göteborg.

The aim of the study was to describe dental health status among middle-aged and elderly women over a 24-year period. Because of the design of the study it was possible to make both longitudinal and cross-sectional comparisons. The study started in 1968-69 with a combined medical and dental examination of women aged between 38 and 60 years. New dental examinations of these same women were performed in 1980-81 and again in 1992-93, and included new cohorts of 38-year-old women on both occasions. In the cross-sectional perspective, it was shown that the number of edentate individuals decreased significantly during the 24-year period. Among dentate women, the number of remaining teeth and restored teeth increased significantly cross-sectionally. However, the youngest age group, women of 38 years, showed a lower number of restored teeth in the latest study (in 1992-93). There was also a lower number of crowns, root-fillings, and pontics in the latest study for the youngest age group. The two older age groups studied cross-sectionally showed similar numbers in all studies. In the longitudinal study, there was a decrease with time in incidence of edentulism. Among the dentate women in the longitudinal study the number of restored teeth related to those remaining was high (range 76-90%) and did not change much between the studies in the different age groups. There was a clear tendency during the 24-year period in all age groups for more teeth to be restored with crowns rather than different fillings. In conclusion, this population study, with a follow-up of 24 years, shows that dental status improved in that fewer individuals lost all their teeth and younger age groups have more remaining teeth and fewer restorations than previously.

Adult↗
PubMed1999

Periodontal bone height in professional musicians. Cross-sectional and longitudinal aspects.

Cross-sectional and longitudinal studies of the periodontal bone height were performed on professional musicians playing wind and non-wind instruments. The cross-sectional study population included 244 occupational musicians (186 men and 58 women aged 20-69 years) from three Swedish national orchestras. Eighty-seven were wind instrument musicians. Radiographic full-mouth surveys were performed and the periodontal bone height was measured with a computerized method and expressed as a percentage of the root length. The mean periodontal bone height was 83.4% for the musicians playing wind instruments and 83.6% for those playing non-wind instruments. There was no statistically significant difference in periodontal bone height between the two instrumentalist categories. In addition, the bone height quotients of anterior to posterior teeth were analyzed but no significant differences were found between wind and non-wind instrumentalists. A longitudinal cohort including 92 musicians who had been examined in a corresponding study 10 years earlier was studied. The overall loss of the periodontal bone height over the 10-year period was small, but only wind instrumentalists of the 50-69 year age group exhibited a statistically significant reduction over time. There was no statistically significant difference between musicians as regards instrument played. It is concluded from the cross-sectional and 10-year longitudinal observations that the playing of wind instruments is unlikely to affect periodontal bone height.

Adult↗
PubMedDate not supplied

Occupational noise exposure and blood pressure: longitudinal and cross-sectional observations in a group of underground miners.

The question of an association between occupational noise exposure and blood pressure has important public health implications. The harmful effects of hypertension are well known, and noise is considered the most pervasive of all occupational exposures. Most previous studies have looked cross-sectionally at blood pressure and noise exposures in workers. The present study examined historic medical and personnel records of 2,197 white male South African miners. At approximately 3-y intervals, the job title, diastolic and systolic blood pressures, height, weight, and use of medication for hypertension were recorded. Noise levels were estimated, based on noise measurements of individual jobs and work areas. In the cross-sectional analyses, multiple linear regression was used with blood pressure as the dependent variable; age, body mass index (BMI), and noise exposure were the independent variables. Longitudinal analyses were performed for those miners who had observations at four or more time periods, by calculating regression coefficients for individuals for blood pressure and noise, controlling for age and BMI. Additional longitudinal analyses compared blood pressure changes between two points in time for individual miners with changes in noise exposure, controlling for changes in age and BMI. The results of the cross-sectional and longitudinal analyses indicated no association between blood pressure and noise exposure. On the basis of these results, it does not appear that occupational noise exposure has an effect on blood pressure. Inconsistencies in the literature and shortcomings in the present study indicate that additional study is needed.

Adult↗
PubMed1997

Children's ability to delay gratification: longitudinal relations to mother-child attachment.

Concurrent and longitudinal mother-child attachment qualities were studied in relation to children's ability to postpone gratification at age 6 years. A sample of 32 children (at ages 12 months and 18 months) and their mothers participated in the strange situation procedure. At age 6 years, they were observed in an attachment situation and administered a standard delay of gratification task. The length of time that children were able to delay gratification at age 6 was predicted both by concurrent attachment quality and by a longitudinal attachment measure. Children with secure attachment were able to wait the longest periods of time, whereas those with insecure-disorganized attachment had the most difficulties in waiting. The effects of longitudinal, but not concurrent, attachment quality on children's total waiting time remained significant when other important variables were considered, including gender and children's cognitive functioning. An interactive effect was found between attachment quality and cognitive functioning. Insecure-avoidantly attached children with high cognitive functioning did not differ in their overall waiting times from securely attached children, but insecure-avoidantly attached children with average or low cognitive functioning did have shorter waiting times. The study provides a basis for the further investigation of mother-child attachment quality as a factor that is linked to children's delay behavior.

Attention↗
PubMedDate not supplied

Changes in semen quality in Jerusalem between 1990 and 2000: a cross-sectional and longitudinal study.

The aim of the present study was to investigate whether sperm quality has changed during the years 1990-1999 among men residing in Jerusalem, Israel, who were involved in treatment by intrauterine insemination (IUI). Both cross-sectional and longitudinal analyses were performed. A total of 2638 male partners in couples that underwent treatment by IUI participated in the cross-sectional investigation. Of them, 417 men (16%) were included in the longitudinal study. Total sperm counts and percent motility were evaluated on an annual basis to assess changes over 10 years from 1990 through 1999. A significant downward trend in sperm count and motility was demonstrated in the cross-sectional study. Sperm count decreased by 5.2 x 10(6)+/-0.9 x 10(6) (p<.0001) each year and percent motility declined by 0.50+/-0.14% (p=.0003). Similar changes were found in the longitudinal evaluation, but they were not statistically significant. These data suggest that during the last decade in Jerusalem, sperm count and motility declined significantly among men involved in infertile relationships and treated by IUI.

Cross-Sectional Studies↗
PubMed2003

Participation bias in longitudinal studies: experience from the Population Study of Women in Gothenburg, Sweden.

OBJECTIVE: To describe a cohort study of women receiving a series of comprehensive health examinations over 32 years. DESIGN: Longitudinal population study based on a randomised sample of the female population from defined age cohorts. SETTING: City of Göteborg, Sweden. SUBJECTS: Subjects were 38, 46, 50, 54 or 60 years old at the start of the study in 1968. Re-examinations were performed in 1974, 1982 and 1992. Non-participants in the most recent examination, initiated in 2000, were offered home visits. MAIN OUTCOME MEASURES: Participation, anthropometric and blood pressure changes. RESULTS: At the end of the 32-year follow-up, 64% of the original participants were alive, and low participation among survivors was a problem. An acceptable participation rate (71% of those alive) was obtained after home visits were offered. Surviving non-participants already had elevated cardiovascular risk factors at onset of the study in 1968, along with lower educational level and lower socioeconomic status. Home visited subjects were similar to non-participants with regard to anthropometry and blood pressure, but did not differ from participants with regard to social indicators. Thirty-two-year longitudinal data demonstrate clear ageing effects for several important variables, which should, however, be considered in the context of documented differences with non-participants at the baseline examination. CONCLUSIONS: Longitudinal studies in elderly populations provide important data on changes during the ageing process. However, participation rates decline for a number of reasons and generalisations should be made with care. Moreover, including home visits in the protocol can both increase participation and reduce participation bias in elderly cohorts.

Adult↗
PubMed1999

Thymus size in infants from birth until 24 months of age evaluated by ultrasound. A longitudinal prediction model for the thymic index.

PURPOSE: To do a follow-up sonography assessment of the thymic size in infants at an age of 24 months, and to create a longitudinal prediction model for the thymic index covering all ages from birth to 24 months. MATERIAL AND METHODS: Of 37 infants examined in an earlier investigation, 34 attended a 24-month follow-up examination. The thymic index, a volume estimate, was assessed by sonography and compared to clinical variables, breast-feeding status and illness. The longitudinal prediction model was based on data throughout 2 years. RESULTS: There was no significant relation between the thymic index and the clinical variables, breast-feeding status or illness at 24 months. An overall test for the effect of breast-feeding status at 4 months for infants from 0-24 months was significant, as was the actual body length of the infants from 0-8 months. Prediction models were estimated. CONCLUSION: Based on a 24-month longitudinal sonography study, prediction models are presented whereby the thymic size, as an index, can be predicted at all times from birth to 24 months of age.

Child Development↗
PubMedDate not supplied

Changes in metacarpal bone mineral density with age and menopause using computed X-ray densitometry in Japanese women: cross-sectional and longitudinal study.

BACKGROUND: Bone mineral density (BMD) loss with age and menopause is widely accepted in elderly women. However, only a few studies have utilized a multiple regression model that includes physical characteristics to assess comprehensive lifetime changes in BMD. OBJECTIVE: A prospective study was conducted to characterize the normal patterns in metacarpal BMD changes in Japanese women, and to assess the applicability of a fitting model using cross-sectional data compared with longitudinal variability. SUBJECTS AND METHODS: The study consisted of 5422 healthy women in cross-sectional data and a 1-year follow-up of 359 women. The metacarpal BMD was measured by computed X-ray densitometry. Multiple linear and nonlinear regression analyses were performed in cross-sectional subjects. Nonparametric analysis was used to compare percentage rates of BMD changes between actual and estimated values. RESULTS: The cross-sectional data showed that the best-fit equation was a nonlinear change model using the variables of age and height in premenopausal women, and years since menopause (YSM), age and height in postmenopausal women. The results of longitudinal data indicated the following. In premenopausal women, the actual BMD changes were greater in the 30-39 age group than the 20-29 age group and were less in the 50-59 group than the 40-49 group. The rates of annual change in BMD between the actual value and estimated value by change model were very similar. In postmenopausal women, the actual changes in BMD indicated that the rapid rate of reduction observed was over 3% at 0-5 YSM and 1.5% at 6-10 YSM, and thereafter showed a slower rate of decline at 11 YSM. The change model represented the trend of actual change in BMD for postmenopausal women, whereas the rates of estimated BMD loss underestimated the actual changes at 1-10 YSM. CONCLUSION: The change model for premenopausal women using cross-sectional data is beneficial in evaluating the actual metacarpal BMD variability, whereas that for postmenopausal women is insufficient in estimating the longitudinal BMD variability.

Adult↗
PubMedDate not supplied

A longitudinal study of osteoarthritis of the hand: the effect of age.

Osteoarthritis is the most ubiquitous rheumatic disease worldwide. Although its prevalence in various populations has been well documented, few studies have evaluated the longitudinal radiographic progression of the disease, especially as it is expressed in the interphalangeal joints of the hand. In this longitudinal study, left hand-wrist X-rays of 386 white male participants of the Baltimore Longitudinal Study of Aging followed for at least 5 years with two or more visits were examined for prevalence and progression of osteoarthritis of the distal and proximal interphalangeal joints of the hand. As other studies have shown, we found that the prevalence of osteoarthritis in both distal and proximal interphalangeal joints becomes progressively higher as the age of the subjects increases. Using the life table method of analysis we studied the progression of osteoarthritis as defined by the following criteria: (1) an increase in the severity of radiographic changes of the joints previously affected and (2) an increase in the number of new joints affected. The results indicated that osteoarthritis in both the distal and proximal interphalangeal joints progresses at a faster rate in the older population than in individuals less than 60 years of age. Furthermore, osteoarthritis in the interphalangeal joints progresses at the same rate whether the starting point was a Kellgren grade of 0 (no disease) or 1 (doubtful). We therefore conclude that grade 1 is an intermediate step in the inexorable progression of osteoarthritis of the interphalangeal joints and not synonymous with grade 0, as it has been customarily interpreted.

Adolescent↗
PubMedDate not supplied

Modeling incomplete longitudinal and cross-sectional data using latent growth structural models.

In this paper we describe some mathematical and statistical models for identifying and dealing with changes over age. We concentrate specifically on the use of a latent growth structural equation model approach to deal with issues of: (1) latent growth models of change, (2) differences in longitudinal and cross-sectional results, and (3) differences due to longitudinal attrition. This is a methodological paper using simulated data, but we base our models on practical and conceptual principles of modeling change in developmental psychology. Our results illustrate both benefits and limitations using structural models to analyze incomplete longitudinal data.

Aging↗