This study, examining the longitudinal relation among physical activity, body mass index, and development of type 2 diabetes in a high-risk population, is unique because diabetes was determined by ...oral glucose tolerance testing rather than by self-report. A physical activity questionnaire assessing past year leisure and occupational activity was administered to 1,728 nondiabetic Pima individuals aged 15–59 years as part of a series of clinic examinations in the Gila River Indian Community from 1987 to 2000. During an average follow-up period of 6 years, 346 subjects developed diabetes. Using time-dependent Cox proportional hazards modeling adjusting for age, the authors found that total activity was related to diabetes incidence in women and men (p < 0.05 in women only). After additional adjustment for body mass index, the relation between activity and diabetes incidence was weakened in both men and women. When the age-adjusted diabetes incidence rates were examined by levels of activity stratified by tertile of body mass index, the diabetes incidence rate remained lower in more active than in less active men and women from all body mass index groups, with the exception of the middle body mass index tertile in men (p < 0.05 in women only). These results suggest that the adoption and maintenance of a physically active lifestyle can play a significant role in preventing type 2 diabetes.
Summary
In the Diabetes Prevention Program Outcome Study (DPPOS), a cohort at high risk of diabetes, randomization to intensive lifestyle intervention or metformin, both associated with weight loss, ...did not have long-term negative effects on BMD compared with the placebo group. Potential positive effects of metformin on bone warrant further investigation.
Introduction
Randomization to lifestyle intervention (ILS) or metformin in the Diabetes Prevention Program (DPP) resulted in weight loss and reduced progression to diabetes. Weight loss is associated with reduced bone mineral density (BMD), but the long-term effects of these interventions on BMD are unknown. In the DPP Outcome Study (DPPOS), we determined if randomization to ILS or metformin, compared with placebo, was associated with differences in BMD approximately 16 years later.
Methods
Of 3234 DPP participants, 2779 continued in DPPOS and were offered ILS in group format. Those randomized to metformin were offered unmasked metformin. At DPPOS year 12, 1367 participants had dual-energy X-ray absorptiometry scans. BMD in metformin and ILS groups was compared to placebo using sex-specific linear regression models, adjusted for age, race/ethnicity, and weight and weight-bearing activity at DPP baseline.
Results
At DPPOS year 12, mean age was 66.5 (±9.5) years. Femoral neck BMD was similar in the ILS and placebo groups in men (difference = −0.021 g/cm
2
, 95%CI (−0.063, 0.021)) and in women (+0.014 g/cm
2
, 95%CI (−0.014, 0.042)). Femoral neck BMD was higher in the metformin compared to placebo group although not statistically different in men (+0.017 g/cm
2
, 95% CI (−0.023, 0.058)) and in women (+0.019 g/cm
2
, 95% CI (−0.009, 0.047)). Prevalence of osteoporosis was low and similar across treatment groups in men (0.9%;
p
=0.745) and women (2.4%;
p
=0.466).
Conclusion
In a cohort at high risk of diabetes, lifestyle intervention or metformin did not appear to have long-term negative effects on BMD. Potential positive effects of metformin on bone warrant further research.
Regular physical activity is known to help prevent chronic disease and promote healthy aging. Yet, most older women are not regularly active. This study attempts to identify objectively measured ...attributes of the neighborhood environment that may be associated with physical activity levels in older women.
Sociodemographics and physical activity level, as measured by pedometer, were assessed in 158 overweight Caucasian and African-American postmenopausal women from southwestern Pennsylvania at the baseline evaluation of a randomized clinical trial in 2002–2003. Geographic information systems technology was used to obtain neighborhood-level data, including neighborhood socioeconomic status (SES) indicators, the median year that homes were built (as a proxy measure for urban form), and proximity to businesses and facilities. Multiple linear regression was used to test associations between individuals’ physical activity level and neighborhood characteristics.
After controlling for individual age, race/ethnicity, education, smoking status, and body mass index, indicators of low neighborhood SES, living in a neighborhood with homes built between 1950 and 1969 (representing an urban form that is more pedestrian-friendly than after 1969), and living within walking distance (1500 m) of specific types of businesses and facilities were positively associated with individuals’ physical activity level measured by pedometer (
p <0.05).
Results suggest that certain aspects of the neighborhood environment may have an important influence on the physical activity levels of postmenopausal women. Results warrant future research to clarify the role of these environmental attributes in other populations.
Aims
To compare change in dietary intake, with an emphasis on food groups and food intake behaviour, over time across treatment arms in a diabetes prevention trial and to assess the differences in ...dietary intake among demographic groups within treatment arms.
Methods
Data are from the Diabetes Prevention Program and Diabetes Prevention Program Outcomes Study. Participants were randomized to a lifestyle intervention (n = 1079), metformin (n = 1073) or placebo (n = 1082) for an average of 3 years, after which the initial results regarding the benefits of the lifestyle intervention were released and all participants were offered a modified lifestyle intervention. Dietary intake was assessed using a food frequency questionnaire at baseline and at 1, 5, 6 and 9 years after randomization.
Results
Compared with the metformin and placebo arms, participants in the lifestyle arm maintained a lower total fat and saturated fat and a higher fibre intake up to 9 years after randomization and lower intakes of red meat and sweets were maintained for up to 5 years. Younger participants had higher intakes of poultry and lower intakes of fruits compared with their older counterparts, particularly in the lifestyle arm. Black participants tended to have lower dairy and higher poultry intakes compared with white and Hispanic participants. In the lifestyle arm, men tended to have higher grain, fruit and fish intakes than women.
Conclusions
Changes in nutrient intake among participants in the lifestyle intervention were maintained for up to 9 years. Younger participants reported more unhealthy diets over time and thus may benefit from additional support to achieve and maintain dietary goals.
What's new?
This is the first study to evaluate long‐term changes in food group intake and food behaviours among a large, diverse sample of adults participating in a diabetes prevention trial in the USA.
Significant differences in nutrients and food behaviours were observed between the lifestyle arm and the metformin and placebo arms up to 9 years after randomization.
Key demographic groups at high risk of having poor dietary intake and dietary behaviours were identified and represent an important point for intervention.
This report describes the development and use of two self-report methods and an objective measure to assess longitudinal changes in physical activity in a large biethnic cohort of young girls from ...childhood through adolescence.
The NHLBI Growth and Health Study (NGHS) is a multicenter study of obesity development in 2379 black and white girls followed from ages 9-10 yr to 18-19 yr (NGHS years 1-10). A Caltrac activity monitor was used to objectively quantify activity levels in years 3-5. A 3-d diary (AD) and a habitual patterns questionnaire (HAQ) were administered annually and biannually, respectively, to subjectively quantify physical activity levels. The changing pattern of activities as the girls matured during the 10-yr study period necessitated periodic form changes. Empirical analytic approaches were developed to help distinguish between true longitudinal changes in activity levels from potential numerical artifacts resulting from modifications in forms.
The longitudinal activity data indicate a steep decline in the level of reported activity from baseline to year 10 as indicated by AD scores (446.8 to 292.1 MET-min x d(-1), 35%) as well as by HAQ scores (29.3 to 4.9 MET-times x wk(-1), 83%). This parallel trend in the pattern of the decline in activity among the two self-report methods was mirrored by a similar decline using the Caltrac method of physical activity assessment. From years 3 to 5, the AD decreased by 22%, whereas both the HAQ and Caltrac declined by 21%.
The longitudinal data on physical activity collected in the NGHS cohort further confirm a dramatic decrease in the overall level of physical activity during the transition from childhood to adolescence. The consistency among the three methods indicate that both the AD and HAQ are useful tools for the assessment of activity levels in adolescent girls.
In this longitudinal study of black girls and white girls, the authors measured habitual levels of recreational activity from the age of 8 or 9 through the age of 18 or 19 years. The level of ...physical activity declined precipitously over time, so that by the age of 18 or 19, 56 percent of black girls and 31 percent of white girls reported no habitual recreational activity. Predictors of declines in physical activity among black girls, white girls, or both included lower levels of parental education, higher body-mass index, pregnancy, and cigarette smoking.
By the age of 18 or 19, 56 percent of black girls and 31 percent of white girls report no habitual recreational activity.
Since the early 1960s, the prevalence of obesity in female children and adolescents in the United States has more than doubled, with the greatest increase among black girls.
1
Periodic surveys show no concomitant increase in food intake.
2
,
3
Analogous information on trends in activity level in this population is not available. It has been conjectured that adolescents have become less active in recent years, and that this trend may be responsible for the increased prevalence of obesity.
4
–
8
In cross-sectional studies, activity levels have been reported to drop by as much as 50 percent during adolescence.
7
,
8
Although white girls . . .
Objective
Empirical evidence supports an inverse relationship between physical activity (PA) and adiposity, but studies using detailed measures of both are scarce. The relationship between regional ...adiposity and accelerometer‐derived PA in men and women are described.
Design and Methods
Cross‐sectional analysis included 253 participants from a weight loss study limited to ages 20‐45 years and BMI 25‐39.9 kg m−2. PA data were collected with accelerometers and expressed as total accelerometer counts and average amount of time per day accumulated in different intensity levels sedentary, light‐, and moderate‐to‐vigorous intensity PA (MVPA). Accumulation of time spent above 100 counts was expressed as total active time. Computed tomography (CT) was used to measure abdominal and adipose tissue (AT). Multivariate linear regression analyses were used to assess the relationship between regional adiposity (dependent variable) and the various PA levels (independent variable), and were executed separately for men and women, adjusting for wear time, age, race, education, and BMI.
Results
Among males, light activity was inversely associated with total AT (β = −0.19; P = 0.02) as well as visceral AT (VAT) (β = −0.30; P = 0.03). Among females sedentary time was positively associated with VAT (β = 0.11; P = 0.04) and total active time was inversely associated with VAT (β = −0.12; P = 0.04).
Conclusions
Findings from this study suggest that PA intensity level may influence regional adiposity differently in men and women. Additional research is needed in larger samples to clarify the difference in these associations by sex, create recommendations for the frequency, duration and intensity of PA needed to target fat deposits, and determine if these recommendations should differ by sex.
The Modifiable Activity Questionnaire (MAQ) is a physical activity questionnaire shown to be both valid and reliable and was initially designed to be interviewer-administered. After translation and ...adaptation into French, the objective of the study was to compare past-year physical activity data obtained by self-administration of this questionnaire and by interviewer-administration.
84 subjects (22 men, 62 women, age 36-63 yr) enrolled in an ongoing prospective study in France (the SUpplementation en VItamines et Minéraux AntioXydants or SU.VI.MAX study) completed both versions of the questionnaire in a randomized order with a mean (SD) delay of 7.9 (5.8) d between the two modes. Past-year leisure and occupational physical activity were expressed as both h x wk(-1) and MET-h x wk(-1) of activity, and television watching was expressed as h x d(-1). Analysis of variance on ranks was used to compare activity variables obtained by self-administration and interview. Agreement was assessed by nonparametric intraclass correlation coefficients.
A significant effect of the mode of administration was found only for past-year leisure physical activity with lower values reported in self-administered conditions compared with interview. However, a high level of concordance between the two modes of administration was observed for all variables as shown by the intraclass correlation coefficients: 0.90 for leisure physical activity (h x wk(-1)), 0.82 for occupational activity (h x wk(-1)), 0.83 for total (leisure and occupational combined) physical activity (h x wk(-1)), and 0.97 for television viewing (h x d(-1)).
The agreement between the two modes of administration of the questionnaire suggests that the self-administered version of the MAQ is a valuable tool to assess past-year physical activity and inactivity in self-administered conditions. This instrument could be used in large-scale population studies investigating the relationships between physical activity and health outcomes.
The reproducibility and validity of a past year physical activity questionnaire was determined in a sample of 100 adolescents aged 15-18 years, randomly selected from a population-based cohort. ...Subjects completed four 7-day recalls of activity approximately 3 months apart. The average of the four 7-day recalls of activity was utilized as the "gold standard" against which the past year questionnaire was compared to evaluate validity. The questionnaire was also validated against objective measures, such as physical fitness and body mass index. Interscholastic team rosters were utilized to directly validate the reporting of specific activities. One-month and one-year test-retest reproducibility of the questionnaire were determined. For different measures of activity, the Spearman correlations between the questionnaire and the average of the 7-day recalls ranged from 0.55 to 0.67 in males and 0.73 to 0.83 in females, all significant at p < 0.01. In general, although there was no association between the past year activity questionnaire results and objective measures, there was a significant, albeit weak association between the physical activity questionnaire and time to complete a 1-mile (1.61-km) run (r = -0.47) in females. Subjects reported participating in specific interscholastic sports with an accuracy of 100%, 86%, and 95% for the fall, winter, and spring sports, respectively. Test-retest reproducibility was higher over one month (r = 0.79) than over one year (r = 0.66). These data provide evidence that the questionnaire yields a reasonable estimate of past year or "habitual" physical activity in adolescents.
Quantitative ultrasound (QUS) is a simple, inexpensive and non-invasive measure of bone which has been used in research settings for the prediction of osteoporosis. This review summarizes the current ...status of the epidemiology of QUS analysis, including its relationship with bone mineral density (BMD), risk of osteoporotic fracture and risk factors for osteoporosis. Although only moderately correlated with BMD, QUS appears to be as strong a predictor of osteoporotic fracture as BMD and may predict fracture independent of BMD. Risk factors for low QUS, including age, menopause, body composition and physical inactivity, seem to parallel those of low BMD. More longitudinal research is needed to confirm the clinical utility of QUS and more experimental and population-based studies are needed to determine whether the etiology of low QUS values is different from that of low bone mass.
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