Weight gain continues in the 1990s: 10-year trends in weight and overweight from the CARDIA study. Coronary Artery Risk Development in Young Adults
ABSTRACT The prevalence of obesity increased in the United States through the 1980s. The authors examined 10-year aging and secular (time-related) trends in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort for indications of whether these trends are continuing and for ages of peak weight gain in young adults. CARDIA is a population-based, prospective study of 5,115 African-American and White men and women aged 18-30 years at baseline. Body weight and overweight prevalence were measured at five time points from 1985-1986 to 1995-1996. Linear, mixed-model regression was used to partition weight gain into that due to secular trends and that due to aging. Prevalence of overweight (body mass index (BMI) > or = 25.0 kg/m2) increased markedly, and prevalence of severe obesity (BMI > or = 40.0 kg/m2) doubled in all race-sex groups. Each race-sex group experienced significant secular weight gains, ranging from 0.96 kg/year (95% confidence interval: 79, 1.13) in African-American women to 0.55 kg/year (95% confidence interval: 0.41, 0.69) in White women. Significant secular gains were present during each follow-up period. Each race-sex group also experienced significant weight increases related to aging during their early to midtwenties. Secular trends for weight gain are continuing in CARDIA, but the magnitude of weight gain differed among the four race-sex groups.
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- "our sample was C0 . 9 kg , with an average weight gain of 2 . 5 kg among those who gained weight . The net weight gain observed here is consistent with weight changes reported in other studies of college students ( Lloyd - Richardson et al . , 2009 ) . Small incremental weight gain over time is associated with overweight and obesity in adulthood ( Lewis et al . , 2000 ) . Thus , our findings indicate that many students experienced clinically significant weight gain during the first nine weeks of the first semester . Our findings are limited by the use of self - reported data , which may carry risks for inaccuracy and / or expectancy bias , although quality checks were used to minimize these risks ( e"
ABSTRACT: We hypothesized that shorter sleep durations and greater variability in sleep patterns are associated with weight gain in the first semester of university. Students (N = 132) completed daily sleep diaries for 9 weeks, completed the MEQ (chronotype) and CES-D (depressed mood) at week 9, and self-reported weight/height (weeks 1 & 9). Mean and variability scores were calculated for sleep duration (TST, TSTv), bedtime (BT, BTv), and wake time (WT, WTv). An initial hierarchical regression evaluated (block 1) sex, ethnicity; (block 2) depressed mood, chronotype; (block 3) TST; (block 4) BT, WT; and (block 5; R(R) change = 0.09, p = 0.005) TSTv, BTv, WTv with weight change. A sex-by-TSTv interaction was found. A final model showed that ethnicity, TST, TSTv, and BTv accounted for 31% of the variance in weight change for males; TSTv was the most significant contributor (R(R) change = 0.21, p < 0.001). Daily variability in sleep duration contributes to males' weight gain. Further investigation needs to examine sex-specific outcomes for sleep and weight.Behavioral Sleep Medicine 08/2014; DOI:10.1080/15402002.2014.940109 · 2.34 Impact Factor
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- "Most past studies that have focused on BMI trends over time were based on repeated cross-sectional samples [23,24] or single cohort studies [25,26]. In repeated cross-sectional studies of different samples of a population, it is difficult to determine whether observed weight gain reflects true age effects or merely age differences in the characteristics of the repeated samples. "
ABSTRACT: The aim of this longitudinal study was to analyze whether mean Body Mass Index (BMI), assessed at four occasions, changed within different age groups and birth cohorts over time, i.e., between 1980/81 and 2004/05, after adjustment for possible confounders. A sample of 2728 men and 2770 women aged 16--71 years at study start were randomly drawn from the Swedish Total Population Register and followed from 1980/81 to 2004/05. The same sample was assessed on four occasions during the 24-year study period (i.e., every eighth year). The outcome variable, BMI, was based on self-reported height and weight. A mixed model, with random intercept and random slope, was used to estimate annual changes in BMI within the different age groups and birth cohorts. Mean BMI increased from 24.1 to 25.5 for men and from 23.1 to 24.3 for women during the 24-year study period. The annual change by age group was highest in the ages of 32--39, 40--47 and 48--55 years among men, and in the ages of 24--31, 32--39, and 40--47 years among women. The highest annual changes were found in the youngest birth cohorts for both men and women, i.e., those born 1958--65, 1966--73, and 1974--81. For each birth cohort, the annual change in BMI increased compared to the previous, i.e., older, birth cohort. In addition, age-by-cohort interaction tests revealed that the increase in BMI by increasing age was higher in the younger birth cohorts (1966--1989) than in the older ones. Public health policies should target those age groups and birth cohorts with the highest increases in BMI. For example, younger birth cohorts had higher annual increases in BMI than older birth cohorts, which means that younger cohorts increased their BMI more than older ones during the study period.BMC Public Health 09/2013; 13(1):893. DOI:10.1186/1471-2458-13-893 · 2.26 Impact Factor
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- "Conventional thought was that human biology included homeostatic feedback mechanisms designed to regulate body weight  . The average adult gains approximately 0.5 kg per year, which translates to approximately 3500 kcal surplus    . Given an average consumption of approximately 900,000 kcal per year  , this equals only about a 0.5% discrepancy, suggesting that homeostatic regulation of energy balance is relatively tight . "
ABSTRACT: Weight loss dieting remains the treatment of choice for the vast majority of obese individuals, despite the limited long-term success of behavioral weight loss interventions. The reasons for the near universal unsustainability of behavioral weight loss in [formerly] obese individuals have not been fully elucidated, relegating researchers to making educated guesses about how to improve obesity treatment, as opposed to developing interventions targeting the causes of weight regain. This article discusses research on several factors that may contribute to weight regain following weight loss achieved through behavioral interventions, including adipose cellularity, endocrine function, energy metabolism, neural responsivity, and addiction-like neural mechanisms. All of these mechanisms are engaged prior to weight loss, suggesting that so called "anti-starvation" mechanisms are activated via reductions in energy intake, rather than depletion of energy stores. Evidence suggests that these mechanisms are not necessarily part of a homeostatic feedback system designed to regulate body weight or even anti-starvation mechanisms per se. Though they may have evolved to prevent starvation, they appear to be more accurately described as anti-weight loss mechanisms, engaged with caloric restriction irrespective of the adequacy of energy stores. It is hypothesized that these factors may combine to create a biological disposition that fosters the maintenance of an elevated body weight and work to restore the highest sustained body weight, thus precluding the long-term success of behavioral weight loss. It may be necessary to develop interventions that attenuate these biological mechanisms in order to achieve long-term weight reduction in obese individuals.Physiology & Behavior 08/2013; 120. DOI:10.1016/j.physbeh.2013.07.009 · 2.98 Impact Factor