Obesity, disability, and mortality: a puzzling link

Higher abdominal adiposity is associated with higher lean muscle mass but lower muscle quality in middle-aged and older men and women: the Framingham Heart Study

BACKGROUND

The objective was to determine if abdominal fat is related to poor muscle health.

METHODS

This cross-sectional study included 428 males and 534 females with appendicular lean mass (ALM, kg) from dual-energy X-ray absorptiometry (DXA), grip strength (kg), and upper extremity muscle "quality" (grip strength/arm lean mass) measured (1996-2001) in the Framingham Offspring Study. Sex-specific linear regressions associated adiposity measures [waist circumference (WC, cm) and visceral adipose tissue (VAT, cm3), and subcutaneous adipose tissue (SAT, cm3)] as Z-scores with each measure of muscle, adjusting for covariates. Models were further stratified by body mass index (BMI, < 30, ≥ 30 kg/m2).

RESULTS

Mean (± SD) age was 60 ± 9 years and BMI was 28.9 ± 4.6 kg/m2 (men) and 27.7 ± 5.8 kg/m2, (women). In men, the BMI-stratified analyses showed higher WC was associated with higher ALM (P < 0.0001 each) but with lower muscle quality (P < 0.02) in both BMI groups. Higher SAT was also associated with higher ALM (P = 0.0002) and lower muscle quality (P = 0.0002) in men with BMI < 30, but not in obese men. In women, higher WC, SAT, and VAT were each associated with higher ALM but lower muscle quality, particularly in obese women. Higher SAT (P = 0.05) and VAT (P = 0.04) were associated with higher quadriceps strength in women with BMI < 30 kg/m2 but not in obese women.

CONCLUSIONS

Higher abdominal fat may be associated with greater lean mass but poorer muscle quality, particularly in obese women. This suggests that adipose tissue may have endocrine influences on muscle, which should be confirmed in longitudinal studies.

Relationship Between Weight-Change Patterns and Cognitive Function: A Retrospective Study

BACKGROUND

Obesity has been linked to cognitive impairment. However, how changes in body mass index (BMI) over the life course influence cognitive function remains unclear.

OBJECTIVE

The influence of distinct weight-change patterns from young adulthood to midlife and late adulthood on cognitive function in older adults was explored.

METHODS

A total of 5,809 individuals aged≥60 years were included and categorized into four groups on the basis of BMI change patterns. Cognitive function was assessed using four cognition tests in the baseline survey. The relationship between the weight-change patterns and cognition was evaluated using regression models.

RESULTS

In comparison with participants who remained at non-obese, those moving from the non-obese to obese weight-change pattern from young (25 years of age) to middle adulthood showed lower Digit Symbol Substitution Test (DSST) scores (β= -1.28; 95% confidence interval [CI]: -2.24 to -0.32). A non-obese to obese change pattern from age 25 years of age to 10 years before baseline was associated with a higher risk of DSST impairment (odds ratio = 1.40; 95% CI: 1.09 to 1.79). In comparison with participants whose heaviest weight was recorded after 60 years of age, those with the heaviest weight between 18 and 40 years of age had lower DSST scores (β= -1.46; 95% CI: -2.77 to -1.52).

CONCLUSION

Our results suggest that the transition from the non-obese to obese category in early adulthood and appearance of the heaviest weight between 18 and 40 years of age are associated with lower cognitive function in later life.

Effects of weight change on all causes, digestive system and other causes mortality in Southern Italy: a competing risk approach

Weight change is associated with all causes of death, cardiovascular, and cancer mortality and a heterogeneous group of other causes of death. We aimed to estimate the effect of weight change on all causes and cause-specific mortality in a cohort with a high prevalence of deaths due to diseases of the digestive system.MethodsIn this prospective cohort study, 2230 subjects aged 30 to 50 years were examined. The study consisted of a 32-year longitudinal study period (January 1985 to December 2017) and mortality follow-up. Outcomes were mortality from all causes and deaths from gastrointestinal disease. Root Mean Squared Error (RMSE) was evaluated to capture individual residual variation in Body Mass Index (BMI) after adjustment for baseline BMI, and the relationship of residual variation with mortality was calculated as cumulative incidence function and cause-specific hazard (CSH) rate.ResultsIn total, 793 participants died during the follow-up, 96 of them due to Digestive system causes. Magnitude of residual variation weight in the last quintile was associated with all-cause mortality (relative risk, 2.00; 95% CI, 1.54-2.59) and Digestive system causes (relative risk, 3.82; 95% CI, 1.86-7.81).ConclusionThe findings suggest an association between weight change and gastrointestinal disease mortality. Epidemiological works studying the correlation between weight change and mortality should consider this aspect.

Quantifying the Varying Predictive Value of Physical Activity Measures Obtained from Wearable Accelerometers on All-Cause Mortality over Short to Medium Time Horizons in NHANES 2003-2006

Physical activity measures derived from wearable accelerometers have been shown to be highly predictive of all-cause mortality. Prediction models based on traditional risk factors and accelerometry-derived physical activity measures are developed for five time horizons. The data set contains 2978 study participants between 50 and 85 years old with an average of 13.08 years of follow-up in the NHANES 2003–2004 and 2005–2006. Univariate and multivariate logistic regression models were fit separately for five datasets for one- to five-year all-cause mortality as outcome (number of events 46, 94, 155, 218, and 297, respectively). In univariate models the total activity count (TAC) was ranked first in all five horizons (AUC between 0.831 and 0.774) while the active to sedentary transition probability (ASTP) was ranked second for one- to four-year mortality models and fourth for the five-year all-cause mortality model (AUC between 0.825 and 0.735). In multivariate models age and ASTP were significant in all one- to five-year all-cause mortality prediction models. Physical activity measures are consistently among the top predictors, even after adjusting for demographic and lifestyle variables. Physical activity measures are strong stand-alone predictors and substantially improve the prediction performance of models based on traditional risk factors.

The Impact of Smoking and Obesity on Disability-Free Life Expectancy in Older Australians

BACKGROUND

Smoking and obesity are 2 modifiable risk factors for disability. We examine the impact of smoking and obesity on disability-free life expectancy (DFLE) at older ages, using 2 levels of disability.

METHOD

We used the DYNOPTA dataset, derived by harmonizing and pooling risk factors and disability outcomes from 5 Australian longitudinal aging studies. We defined mobility disability as inability to walk 1 km, and more severe (activities of daily living [ADL]) disability by the inability to dress or bathe. Mortality data for the analytic sample (N = 20 401; 81.2% women) were obtained from Government Records via data linkage. We estimated sex-specific total life expectancy, DFLE, and years spent with disability by Interpolated Markov Chain (IMaCh) software for each combination of smoking (never vs ever), obesity (body mass index ≥30 vs 18.5 to <30), and education (left school age 14 or younger vs age 15 or older).

RESULTS

Compared to those without either risk factor, high educated nonobese smokers at age 65 lived shorter lives (men and women: 2.5 years) and fewer years free of mobility disability (men: 2.1 years; women: 2.0 years), with similar results for ADL disability. Obesity had the largest effect on mobility disability in women; high educated obese nonsmoking women lived 1.3 years less than nonsmoking, not obese women but had 5.1 years fewer free of mobility disability and 3.2 fewer free of ADL disability. Differences between risk factor groups were similar for the low educated.

CONCLUSIONS

Our findings suggest eliminating obesity would lead to an absolute reduction of disability, particularly in women.

Carotenoids, vitamin A, and their association with the metabolic syndrome: a systematic review and meta-analysis

Context

Modifiable factors that reduce the burden of the metabolic syndrome (MetS), particularly plant-derived biomarkers, have been a recent focus of rising interest.

Objective

This systematic review and meta-analysis, which follows PRISMA guidelines, evaluates evidence from a period of 20 years that links vitamin A and carotenoids with the occurrence of MetS and following the PRISMA guidelines.

Data Sources

PubMed and Cochrane databases (January 1997 through March 2017) were systematically assessed for studies, including case-control, cross-sectional, and cohort studies, that evaluated the associations of MetS with carotenoids and retinyl esters and retinol (vitamin A).

Data Extraction

Key measures of associations were harmonized into odds ratios (ORs) and 95% confidence intervals (95%CI) of MetS per 1 standard deviation (SD) of exposure using forest plots and random effects models that pooled data points from 11 cross-sectional studies. Begg's funnel and harvest plots were constructed.

Results

An inverse association between total carotenoids and MetS was found [ORpooled, 0.66; 95%CI, 0.56-0.78; 1 SD ∼ 0.82 µmol/L; n = 5 studies]. This association was the strongest for β-carotene, followed by α-carotene and β-crypotoxanthin. No association was detected between retinol and MetS (ORpooled, 1.00; 95%CI, 0.88-1.13; 1 SD ∼ 2.14 µmol/L; n = 6 studies). Publication bias was absent, and harvest plots indicated consistency upon replication for β-carotene and total carotenoid exposures.

Conclusions

This review and meta-analysis suggests that, unlike retinol, total and individual carotenoids were inversely related to MetS.

Longitudinal associations between BMI change and the risks of colorectal cancer incidence, cancer-relate and all-cause mortality among 81,388 older adults : BMI change and the risks of colorectal cancer incidence and mortality

Background

It remains controversial whether weight change could influence the risks of colorectal cancer (CRC) and mortality. This study aimed to quantify the associations between full-spectrum changes in body mass index (BMI) and the risks of colorectal cancer (CRC) incidence, cancer-related and all-cause mortality among midlife to elder population.

Methods

A total of 81,388 participants who were free of cancer and aged 55 to 74 years from the Prostate, Lung, Colorectal, and Ovarian (PLCO) screening program were involved. The percentage change of BMI was calculated as (BMI in 2006 - BMI at baseline)/BMI at baseline, and was categorized into nine groups: decrease (≥ 15.0%, 10.0–14.9%, 5.0–9.9%, 2.5–4.9%), stable (decrease/increase < 2.5%), increase (2.5–4.9%, 5.0–9.9%, 10.0–14.9%, ≥ 15.0%). The associations between percentage change in BMI from study enrolment to follow-up (median: 9.1 years) and the risks of CRC and mortality were evaluated using Cox proportional hazard regression models.

Results

After 2006, there were 241 new CRC cases, 648 cancer-related deaths, and 2361 all-cause deaths identified. Overall, the associations between BMI change and CRC incidence and cancer-related mortality, respectively, were not statistically significant. Compared with participants whose BMI were stable, individuals who had a decrease in BMI were at increased risk of all-cause mortality, and the HRs were 1.21 (95% CI: 1.03–1.42), 1.65 (95% CI: 1.44–1.89), 1.84 (95% CI: 1.56–2.17), and 2.84 (95% CI: 2.42–3.35) for 2.5–4.9%, 5.0–9.9%, 10.0–14.9%, and ≥ 15.0% decrease in BMI, respectively. An L-shaped association between BMI change and all-cause mortality was observed. Every 5% decrease in BMI was associated with a 27% increase in the risk of all-cause mortality (HR = 1.27, 95% CI: 1.22–1.31, p < 0.001). The results from subgroups showed similar trends.

Conclusions

A decrease in BMI more than 5% shows a significantly increased risk of all-cause mortality among older individuals; but no significant association between increase in BMI and all-cause mortality. These findings emphasize the importance of body weight management in older population, and more studies are warranted to evaluate the cause-and-effect relationship between changes in BMI and cancer incidence/mortality.

Weight change across adulthood in relation to all cause and cause specific mortality: prospective cohort study

OBJECTIVE

To investigate the association between weight changes across adulthood and mortality.

DESIGN

Prospective cohort study.

SETTING

US National Health and Nutrition Examination Survey (NHANES) 1988-94 and 1999-2014.

PARTICIPANTS

36 051 people aged 40 years or over with measured body weight and height at baseline and recalled weight at young adulthood (25 years old) and middle adulthood (10 years before baseline).

MAIN OUTCOME MEASURES

All cause and cause specific mortality from baseline until 31 December 2015.

RESULTS

During a mean follow-up of 12.3 years, 10 500 deaths occurred. Compared with participants who remained at normal weight, those moving from the non-obese to obese category between young and middle adulthood had a 22% (hazard ratio 1.22, 95% confidence interval 1.11 to 1.33) and 49% (1.49, 1.21 to 1.83) higher risk of all cause mortality and heart disease mortality, respectively. Changing from obese to non-obese body mass index over this period was not significantly associated with mortality risk. An obese to non-obese weight change pattern from middle to late adulthood was associated with increased risk of all cause mortality (1.30, 1.16 to 1.45) and heart disease mortality (1.48, 1.14 to 1.92), whereas moving from the non-obese to obese category over this period was not significantly associated with mortality risk. Maintaining obesity across adulthood was consistently associated with increased risk of all cause mortality; the hazard ratio was 1.72 (1.52 to 1.95) from young to middle adulthood, 1.61 (1.41 to 1.84) from young to late adulthood, and 1.20 (1.09 to 1.32) from middle to late adulthood. Maximum overweight had a very modest or null association with mortality across adulthood. No significant associations were found between various weight change patterns and cancer mortality.

CONCLUSIONS

Stable obesity across adulthood, weight gain from young to middle adulthood, and weight loss from middle to late adulthood were associated with increased risks of mortality. The findings imply that maintaining normal weight across adulthood, especially preventing weight gain in early adulthood, is important for preventing premature deaths in later life.

Joint and Individual Representation of Domains of Physical Activity, Sleep, and Circadian Rhythmicity

Developments in wearable technology have enabled researchers to continuously and objectively monitor various aspects and physiological domains of real-life including levels of physical activity, quality of sleep, and strength of circadian rhythm in many epidemiological and clinical studies. Current analytical practice is to summarize each of these three domains individually via a standard inventory of interpretable features, and explore individual associations between the features and clinical variables. However, the features often exhibit significant interaction and correlation both within and between domains. Integration of features across multiple domains remains methodologically challenging. To address this problem, we propose to use joint and individual variation explained (JIVE), a dimension reduction technique that efficiently deals with multivariate data representing multiple domains. In this paper, we review the most frequently used features to characterize the domains of physical activity, sleep, and circadian rhythniicity and illustrate the approach using wrist-worn actigraphy data from 198 participants of the Baltimore Longitudinal Study of Aging.

Dairy product consumption and its association with metabolic disturbance in a prospective study of urban adults

The role of dairy foods and related nutrients in cardiometabolic health aetiology is poorly understood. We investigated longitudinal associations between the metabolic syndrome (MetS) and its components with key dairy product exposures. We used prospective data from a bi-racial cohort of urban adults (30-64 years at baseline (n 1371)), the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS), in Baltimore City, MD (2004-2013). The average of two 24-h dietary recalls measured 4-10 d apart was computed at baseline (V1) and follow-up (V2) waves. Annual rates of change (Δ) in dairy foods and key nutrients were estimated. Incident obesity, central obesity and the MetS were determined. Among key findings, in the overall urban adult population, both cheese and yogurt (V1 and Δ) were associated with an increased risk of central obesity (hazard ratio (HR) 1·13; 95 % CI 1·05, 1·23 per oz equivalent of cheese (V1); HR 1·21; 95 % CI 1·01, 1·44 per fl oz equivalent of yogurt (V1)]. Baseline fluid milk intake (V1 in cup equivalents) was inversely related to the MetS (HR 0·86; 95 % CI 0·78, 0·94), specifically to dyslipidaemia-TAG (HR 0·89; 95 % CI 0·81, 0·99), although it was directly associated with dyslipidaemia-HDL-cholesterol (HR 1·10; 95 % CI 1·01, 1·21). Furthermore, ΔCa and ΔP were inversely related to dyslipidaemia-HDL and MetS incidence, respectively, whereas Δdairy product fat was positively associated with incident TAG-dyslipidaemia and HDL-cholesterol-dyslipidaemia and the MetS. A few of those associations were sex and race specific. In sum, various dairy product exposures had differential associations with metabolic disturbances. Future intervention studies should uncover how changes in dairy product components over time may affect metabolic disorders.

Patterns of weight change associated with disease diagnosis in a national sample

BACKGROUND

The incidence and/or diagnosis of a major disease may activate weight change. Patterns of weight change associated with diagnoses have not been systematically documented.

METHODS

We use data on adults ages 30+ in the National Health and Nutrition Examination Survey (NHANES) from 1999-2014. Self-reported current weight and weight one year prior are used to estimate percent weight change in the last year. We use self-reported data on arthritis, diabetes, cancer, cardiovascular disease, liver conditions, and respiratory disease diagnoses to compare weight change among individuals never diagnosed with these conditions, individuals diagnosed 0-1 years ago, and individuals diagnosed 2+ years ago. Multinomial logistic regressions adjust for the presence of multiple conditions.

RESULTS

17.7% of the adult population experienced weight loss of 5.0% or more in the year prior to survey. Individuals diagnosed with any of the conditions were less likely to maintain their weight than those without a diagnosis. Arthritis, diabetes, cancer, cardiovascular disease, and liver conditions were associated with net weight loss, whereas respiratory diseases were associated with higher probabilities of both losing and gaining weight. Among those losing 10% or more, 56.7% had been diagnosed with one of the conditions. Cancer was associated with the highest probability of unintentional weight loss and diabetes with the highest probability of intentional weight loss.

CONCLUSIONS

Disease-associated weight changes leave a distinct imprint on patterns of weight change in the population. Individuals losing at least 10% of their weight in the last year have likely been diagnosed with one of the six conditions.

Vitamin D Metabolism-Related Gene Haplotypes and Their Association with Metabolic Disturbances Among African-American Urban Adults

Epidemiological studies have confirmed associations of the vitamin D receptor (VDR) and vitamin D-related gene polymorphisms with adiposity and other metabolic disturbances. Those associations may be sex-specific. We evaluated the cross-sectional and longitudinal relationships between metabolic disturbances and haplotypes constructed from single nucleotide polymorphisms of VDR (BsmI:G/A: rs1544410; ApaI:A/C: rs7975232; and TaqI:G/A: rs731236) and MEGALIN (rs3755166:G/A; rs2075252:C/T and rs2228171:C/T) genes, in a sample of African-American adults. From 1,024 African Americans participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS, 2004–2013, Baltimore, MD), our analyses included 539 participants with complete genetic, baseline covariate and metabolic outcome data (at baseline and follow-up). Mean ± SD period of follow-up was 4.64 ± 0.93 y. Multivariable-adjusted Cox proportional hazards and logistic regression models were conducted. Among key findings, in men, incident hypertension was inversely related to MEGALIN₁ (GCC), [HR = 0.45, 95% CI: 0.23–0.90, p = 0.024]. Overall, there was a direct, linear dose-response association between VDR₂ (AAG: BAt) and MetS at baseline [OR = 1.60, 95% CI: 1.11–2.31, p = 0.012], while among men, VDR₃ (GAA: bAT) was inversely related to baseline MetS [OR = 0.40, 95% CI: 0.19–0.81, p = 0.011]. In conclusion, VDR and MEGALIN gene variations can affect prevalent MetS and the incidence rate of hypertension, respectively, among African-American urban adults.

Change in body size and mortality: a systematic review and meta-analysis

Background

: Observational studies have reported that weight loss in later life is associated with an increased risk of mortality. However, the association with weight gain is unclear. We conducted a systematic review and meta-analysis of prospective studies assessing the association of weight gain and loss, and mortality.

Methods

: We searched PubMed, Scopus and Web of Science for articles published before 5 September 2015. We included prospective studies that reported enough information to extract hazard ratios (HRs) with the corresponding 95% confidence intervals (CIs) for the association between weight gain and/or weight loss, and all-cause and cause-specific mortality. The estimates were pooled using a random-effects model. Meta-regression models were fitted to explore sources of potential between-study heterogeneity.

Results

: A total of 25 (providing data from 437 772 participants with 34 038 deaths from all causes) and 24 studies (434 694 participants with 31 978 deaths) presented results for the exposures, weight loss and weight gain. Weight loss compared with a stable weight was associated with an increased risk of all-cause (pooled HR: 1.45; 95% CI: 1.34, 1.58), and cardiovascular disease (CVD) mortality (1.50; 1.32, 1.70) and a slightly increased risk of cancer mortality (1.19; 0.97, 1.46). Weight gain was associated with an increased risk of CVD mortality (1.21; 1.07, 1.36) and a slightly increased risk of all-cause mortality (1.07; 1.01, 1.13) and cancer mortality (1.04; 0.96, 1.13). Considerable heterogeneity was observed; the method used to ascertain body size and the proportion of the baseline sample included in the final analysis explained most of the heterogeneity.

Conclusion

: Weight loss and weight gain in midlife are associated with increased risk of all-cause and CVD mortality.

Change in Weight and Body Mass Index Associated With All-Cause Mortality in Korea: A Nationwide Longitudinal Study

CONTEXT

Many studies have reported conflicting evidence on the association between weight change and mortality.

OBJECTIVE

We investigated the association between weight change and subsequent all-cause mortality, using a large-scale, population-based cohort from the National Health Insurance System health checkup data between 2005 and 2015.

METHODS

A total of 11,524,763 subjects older than age 20 years were included. Weight was measured every 2 years and weight change over 4 years was divided into eight categories, from weight loss ≥15% to weight gain ≥20%, for every 5% of weight change. The hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality were analyzed using multivariable Cox proportional hazard models compared with the stable weight group (weight change <5%) after adjusting for age, sex, smoking, drinking, exercise, diabetes mellitus, hypertension, dyslipidemia, cancer, and income.

RESULTS

Weight loss was associated with increased mortality rates compared with weight gain; the group with weight loss ≥15% had the highest HR for all-cause mortality (HR, 2.598; 95% CI, 2.537 to 2.659). The HR for all-cause mortality in the ≥20% weight gain group was 1.784 (95% CI, 1.695 to 1.877). Across all body mass index (BMI) categories, weight loss ≥15% was associated with increased mortality rates and the highest mortality rates were found in the BMI ≥30 kg/m2 group (HR, 3.469; 95% CI, 2.236 to 5.381).

CONCLUSIONS

Weight change over 4 years showed a reverse J-shaped all-cause mortality curve, independent of BMI status. Weight loss was associated with a greater risk of mortality than was weight gain.

Abdominal obesity as a risk factor for disability in Brazilian older adults

OBJECTIVE

To assess the role of abdominal obesity in the incidence of disability in older adults living in São Paulo, Brazil, in a 5-year period.

DESIGN

Longitudinal study, part of the SABE Study (Health, Wellbeing and Aging). We assessed the disability incidence in the period (reported difficulty in at least one activity of daily living (ADL) in 2010) in relation to abdominal obesity in 2006 (waist circumference ≥102 cm in men and ≥88 cm in women). We used Poisson regression to evaluate the association between obesity and disability incidence, adjusting for sociodemographic and clinical factors including BMI.

SETTING

São Paulo, Brazil.

SUBJECTS

Older adults (n 1109) who were independent in ADL in 2006. In 2010, 789 of these were located and re-interviewed.

RESULTS

The crude disability incidence (at least one ADL) was 27·1/1000 person-years in the period. The incidence rate was two times higher in participants with abdominal obesity compared with those without (39·1/1000 and 19·4/1000 person-years, respectively; P<0·001). This pattern was observed in all BMI levels. In regression models, abdominal obesity remained associated with disability incidence (incidence rate ratio=1·90; P<0·03), even after controlling for BMI, gender, age, low grip strength, cognitive impairment, physical inactivity and chronic diseases.

CONCLUSIONS

Abdominal obesity was strong risk factor for disability, showing a more significant effect than BMI, and thus should be an intervention target for older adults. Waist measure is simple, cost-effective and easily interpreted, and therefore can be used in several settings to identify individuals at higher risk of disability.

Physiological wear-and-tear and later subjective health in mid-life: Findings from the 1958 British birth cohort

OBJECTIVE

Our body adapts continuously to environmental challenges and stressful conditions. Allostatic load (AL) is a concept that aims to capture the overall physiological wear-and-tear of the body triggered by the repeated activation of compensatory physiological mechanisms as a response to chronic stress. Growing evidence has shown a link between AL and later health decline, morbidity and mortality. However, due to the global physiological effect captured by the AL concept, it is particularly pertinent to examine its association with subsequent health by taking a broad definition of the latter. We examined the association between AL at 44 years and general health as measured by a latent multidimensional measure of subjective health at 50 years integrating sleep patterns, physical and mental health.

METHODS

AL was constructed using 14 biomarkers representing four physiological systems on 7573 members of the 1958 British birth cohort. Health status was captured using self-reported information about subjective health and summarized using a principal component analysis including: seven dimensions of the SF-36 questionnaire of health-related quality of life, the sleep subscale of the Medical Outcomes Study characterizing quality of sleep patterns, and a malaise inventory score detecting depressive symptoms.

RESULTS

Higher AL score was gradually associated with worse subjective health, after taking into account classic confounders.

CONCLUSIONS

Using a physiological index to grasp how the environment can "get under the skin" leading to poor health is of great interest, permitting a better understanding of life course origins of disease and social gradients in health.

Revealing the burden of obesity using weight histories

Analyses of the relation between obesity and mortality typically evaluate risk with respect to weight recorded at a single point in time. As a consequence, there is generally no distinction made between nonobese individuals who were never obese and nonobese individuals who were formerly obese and lost weight. We introduce additional data on an individual's maximum attained weight and investigate four models that represent different combinations of weight at survey and maximum weight. We use data from the 1988-2010 National Health and Nutrition Examination Survey, linked to death records through 2011, to estimate parameters of these models. We find that the most successful models use data on maximum weight, and the worst-performing model uses only data on weight at survey. We show that the disparity in predictive power between these models is related to exceptionally high mortality among those who have lost weight, with the normal-weight category being particularly susceptible to distortions arising from weight loss. These distortions make overweight and obesity appear less harmful by obscuring the benefits of remaining never obese. Because most previous studies are based on body mass index at survey, it is likely that the effects of excess weight on US mortality have been consistently underestimated.

Quantifying the lifetime circadian rhythm of physical activity: a covariate-dependent functional approach

Objective measurement of physical activity using wearable devices such as accelerometers may provide tantalizing new insights into the association between activity and health outcomes. Accelerometers can record quasi-continuous activity information for many days and for hundreds of individuals. For example, in the Baltimore Longitudinal Study on Aging physical activity was recorded every minute for [Formula: see text] adults for an average of [Formula: see text] days per adult. An important scientific problem is to separate and quantify the systematic and random circadian patterns of physical activity as functions of time of day, age, and gender. To capture the systematic circadian pattern, we introduce a practical bivariate smoother and two crucial innovations: (i) estimating the smoothing parameter using leave-one-subject-out cross validation to account for within-subject correlation and (ii) introducing fast computational techniques that overcome problems both with the size of the data and with the cross-validation approach to smoothing. The age-dependent random patterns are analyzed by a new functional principal component analysis that incorporates both covariate dependence and multilevel structure. For the analysis, we propose a practical and very fast trivariate spline smoother to estimate covariate-dependent covariances and their spectra. Results reveal several interesting, previously unknown, circadian patterns associated with human aging and gender.

Body mass and weight change in adults in relation to mortality risk

Using data from the National Institutes of Health-AARP Diet and Health Study, we evaluated the influence of adulthood weight history on mortality risk. The National Institutes of Health-AARP Diet and Health Study is an observational cohort study of US men and women who were aged 50-71 years at entry in 1995-1996. This analysis focused on 109,947 subjects who had never smoked and were younger than age 70 years. We estimated hazard ratios of total and cause-specific mortality for recalled body mass index (BMI; weight (kg)/height (m)(2)) at ages 18, 35, and 50 years; weight change across 3 adult age intervals; and the effect of first attaining an elevated BMI at 4 successive ages. During 12.5 years' follow-up through 2009, 12,017 deaths occurred. BMI at all ages was positively related to mortality. Weight gain was positively related to mortality, with stronger associations for gain between ages 18 and 35 years and ages 35 and 50 years than between ages 50 and 69 years. Mortality risks were higher in persons who attained or exceeded a BMI of 25.0 at a younger age than in persons who reached that threshold later in adulthood, and risks were lowest in persons who maintained a BMI below 25.0. Heavier initial BMI and weight gain in early to middle adulthood strongly predicted mortality risk in persons aged 50-69 years.

Invited commentary: Body mass index and mortality

In the midst of an epidemic of obesity, epidemiologists are seeking to establish the relationship of body mass index (BMI; weight (kg)/height (m)(2)) with mortality. In an accompanying article, Adams et al. (Am J Epidemiol. 2014;179(2):135-144) used a subsample of the National Institutes of Health-AARP Diet and Health Study cohort, recruited in 1995-1996 (109,947 people), to examine associations of BMI in early (18 years) and middle (35 and 50 years) adulthood with mortality, as well as the effect of weight gain between these ages on subsequent mortality during 12.5 years' follow-up. They report a positive association between BMI and mortality at each age (using BMI 18.5-22.4 as the referent). Furthermore, there were strong positive associations of weight gain between ages 18 and 35 years and ages 35 and 50 years with mortality. Attainment of a BMI of 25 or higher at a younger age increased risk of death. The findings contrast sharply with those of a recent systematic review and meta-analysis of 97 studies, which found that only the grade 2 and 3 obesity categories (i.e., BMI ≥ 35) were responsible for elevated risk of mortality, with slight protection from overweight (25.0-29.9). Due consideration of the limitations of BMI as a measure of detrimental adiposity and of mortality measures alone to inform clinical practice is indicated.

Racial and ethnic differences in obesity and overweight as predictors of the onset of functional impairment

OBJECTIVES

To examine racial and ethnic differences in the effects of body mass index (BMI) on the onset of functional impairment over 10 years of follow-up.

DESIGN

Longitudinal analyses of a cohort from a nationally representative survey of community-dwelling American adults.

SETTING

Six waves (1996-2006) of the Health and Retirement Study (HRS).

PARTICIPANTS

Two groups of HRS participants aged 50 and older without functional impairment at baseline (1996): 5,884 with no mobility difficulty and 8,484 with no activity of daily living (ADL) difficulty.

MEASUREMENTS

Mobility difficulty was a composite measure of difficulty walking several blocks, walking one block, climbing several flights of stairs, and climbing one flight of stairs. ADL difficulty was measured as difficulty in dressing, bathing or showering, eating, and getting in and out of bed without help. The association between baseline BMI and risk of developing functional impairment was estimated using generalized estimating equation models.

RESULTS

Overweight and obesity were significant predictors of functional impairment. Overweight and obese Hispanics were 41% and 91% more likely, respectively, to develop ADL disability than whites in the same BMI categories. Overweight and severely obese blacks were also more likely than their white counterparts to develop ADL disability. Risk of developing ADL difficulty was higher for Hispanics than for blacks in the obese category. No significant differences in onset of mobility difficulty were found between racial or ethnic groups within any BMI category.

CONCLUSION

Blacks and Hispanics were at higher risk than whites of ADL but not mobility impairment. In addition to weight control, prevention efforts should promote exercise to reduce functional impairment, especially for blacks and Hispanics, who are at higher risk.

Assessing the "physical cliff": detailed quantification of age-related differences in daily patterns of physical activity

BACKGROUND

In spite of evidence that physical activity has beneficial effects on health and age-related functional decline, there is a scarcity of detailed and accurate information on objectively measured daily activity and patterns of such activity in older adults.

METHODS

Participants in the Baltimore Longitudinal Study of Aging (n = 611, 50% male, mean age 67, range 32-93) wore the Actiheart portable activity monitor for 7 days in the free-living environment. The association between activity and age was modeled using a continuous log-linear regression of activity counts on age with sex, body mass index, employment status, functional performance, and comorbid conditions as covariates.

RESULTS

In the fully adjusted model, continuous analyses demonstrated that overall physical activity counts were 1.3% lower for each year increase in age. Although there were no differences among morning levels of activity, there was significantly lower afternoon and evening activity in older individuals (p < .01). After adjusting for age, poor functional performance, nonworking status, and higher body mass index were independently associated with less physical activity (p < .001).

CONCLUSIONS

The use of accelerometers to characterize minute-by-minute intensity, cumulative physical activity counts, and daily activity patterns provides detailed data not gathered by traditional subjective methods, particularly at low levels of activity. The findings of a 1.3% decrease per year in activity from mid-to-late life, and the corresponding drop in afternoon and evening activity, provide new information that may be useful when targeting future interventions. Further, this methodology addresses essential gaps in understanding activity patterns and trends in more sedentary sectors of the population.

Obesity and diabetes as accelerators of functional decline: can lifestyle interventions maintain functional status in high risk older adults?

Obesity and diabetes are known risk factors for the development of physical disability among older adults. With the number of seniors with these conditions rising worldwide, the prevention and treatment of physical disability in these persons have become a major public health challenge. Sarcopenia, the progressive loss of muscle mass and strength, has been identified as a common pathway associated with the initial onset and progression of physical disability among older adults. A growing body of evidence suggests that metabolic dysregulation associated with obesity and diabetes accelerates the progression of sarcopenia, and subsequently functional decline in older adults. The focus of this brief review is on the contributions of obesity and diabetes in accelerating sarcopenia and functional decline among older adults. We also briefly discuss the underexplored interaction between obesity and diabetes that may further accelerate sarcopenia and place obese older adults with diabetes at particularly high risk of disability. Finally, we review findings from studies that have specifically tested the efficacy of lifestyle-based interventions in maintaining the functional status of older persons with obesity and/or diabetes.

Prevalence of health conditions and predictors of mortality in oldest old Mexican Americans and non-Hispanic whites

BACKGROUND

The oldest old represent a unique group of older adults. This group is rapidly growing worldwide and yet there are gaps in the knowledge related to their health condition. Ethnic differences in disease prevalence and mortality must be understood to better care for the oldest old.

OBJECTIVE

To compare prevalence of common health conditions and predictors of mortality in oldest old Mexican Americans and non-Hispanic whites.

METHODS

This study included 568 community-dwelling Mexican Americans (MA) aged 85 years and older from the Hispanic Established Population for the Epidemiological Study of the Elderly 2004-2005 and 933 non-Hispanic whites (NHW) of the same age from the Health and Retirement Study 2004. Measures included sociodemographic variables, self-reported medical conditions, activities of daily living (ADLs), and instrumental activities of daily living. Logistic regression analysis was used to examine 2-year mortality in both populations.

RESULTS

Heart attack was significantly more prevalent in oldest old NHW compared with MA, regardless of gender. Conversely, diabetes was significantly more prevalent among MA men and women compared with their NHW counterparts. Compared with NHW men, MA men had significantly higher prevalence of cognitive impairment and hypertension. Additionally, prevalence of hip fracture was significantly higher for MA women compared with NHW women. Significant differences in ADL disability were observed only between both groups of women, whereas significant differences in instrumental activities of daily living disability were observed only between men. MA men and women had higher prevalence of obesity compared with NHW. Predictors of 2-year mortality for both ethnic groups included older age, male gender, and ADL disability. Cognitive impairment was a mortality predictor only for NHW. Similarly, lung disease was a predictor only for MA.

CONCLUSION

Health-related conditions that affect the oldest old vary by gender and ethnicity and entail careful evaluation and monitoring in the clinical setting. Better care requires inclusion of such differences as part of the comprehensive evaluation of the oldest old adults.

Coexistence of Obesity and Anemia in Older Mexican Adults

INTRODUCTION: Developing countries in Latin America (LA) are experiencing rapid aging as a result of advances in medical interventions. This rapid aging has not occurred with comparable improvements in standards of living. Chronic conditions are becoming highly prevalent while exposure to infectious communicable diseases is very common. This unique situation where communicable and non-communicable diseases coexist in the presence of low socioeconomic status place countries in LA in a unique epidemiological situation. Mexico presents a very good example where the impact of this situation on health warrants further analysis. METHODS: We use data from the Mexican National Health and Nutrition Survey (ENSANut 2006), a cross-sectional study representative of all urban and rural areas of Mexico. A total of 5,605 adults older than 60 years of age with valid values for Body Mass Index and Hemoglobin were analyzed. We first included a descriptive analysis of the coexistence of anemia and obesity by age, gender and characteristics of the living environment. We reported the weighted percentages for each covariate by each of four nutritional condition categories (obese and anemic, only-obese, only-anemic, not obese and not anemic). We used multinomial logit regressions to determine the association of socioeconomic characteristics, health status and the living environment with the presence of the three nutritional condition categories. RESULTS: In the ENSANut cohort 10.3% of older adults are anemic, 25.0% are obese and 2.6% are both anemic and obese. Approximately 62% has neither anemia nor obesity. Within the 38% that fall in the three nutritional condition categories, the co-existence of obesity & anemia appears to be associated with metropolitan area residence, living alone, being male, having relatively high wealth, and reporting two or more chronic health conditions. Analyzing the effect of the covariates to distinguish between outcome categories, living environment, age, gender, wealth, and smoking show a significant effect when comparing across the three nutritional categories. CONCLUSIONS: Older Mexican adults with both obesity & anemia have a different profile compared to that of adults with only one of the conditions. Future studies need to do a careful clinical evaluation of this group and design clinical interventions to avoid complications. Additionally, social support initiatives that target specific groups of older adults according to their health and social needs must be established.

Sarcopenia and obesity

Four body composition phenotypes exist in older adults: normal, sarcopenic, obese, and a combination of sarcopenic and obese. There is no consensus, however, on the definitions and classifications of these phenotypes and their etiology and consequences continue to be debated. The lack of standard definitions, particularly for sarcopenia and sarcopenic obesity, creates challenges for determining prevalence across different populations. The etiology of these phenotypes is multifactorial with complex covariate relationships. This review focuses on the current literature addressing the classification, prevalence, etiology, and correlates of sarcopenia, obesity, and the combination of sarcopenia and obesity, referred to as sarcopenic obesity.

Black-white disparity in disability: the role of medical conditions

OBJECTIVES

To describe the independent contributions of selected medical conditions to the disparity between black and white people in disability rates, controlling for demographic and socioeconomic factors.

DESIGN

Cross-sectional analysis of a community-based cohort.

SETTING

Urban and rural counties of central North Carolina.

PARTICIPANTS

Two thousand nine hundred sixty-six adults aged 68 and older participating in the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE).

MEASUREMENTS

Self-reported data on sociodemographic characteristics and medical conditions, Short Portable Mental Status Questionnaire, activities of daily living (ADLs).

RESULTS

Fifty-five percent of the cohort was black. Blacks were more likely than whites to report disability (odds ratio=1.39, 95% confidence interval= 1.15-1.68). Controlling for age, sex, marital status, and socioeconomic status, blacks were more likely to be obese and have diabetes mellitus, and less likely to report vision problems, fractures, and heart attacks. The higher prevalence of obesity and diabetes mellitus in blacks, after adjustment for sociodemographic factors, accounted for more than 30% of the black-white difference in disability. Conversely, the black-white disability gap would be approximately 45% wider if whites had a lower prevalence of fractures and vision impairment, similar to their black peers.

CONCLUSION

Higher rates of obesity and diabetes mellitus in older black Americans account for a large amount of the racial disparity in disability, even after controlling for socioeconomic differences. Culturally appropriate interventions that lower the prevalence or the functional consequences of obesity and diabetes mellitus in blacks could substantially decrease this racial health disparity.

The longitudinal effects of behavioral, health, and socio-demographic factors on body mass index among older Chinese adults

OBJECTIVES

To examine the effects of behavioral, health, and socio-demographic factors on being overweight or obese among older Chinese adults.

METHODS

This research uses panel data from the China Health and Nutrition Survey, which was designed to examine how social and economic transformation affected the health and nutritional status of residents. For these analyses, we used all available information on adults aged 60 years or older surveyed in 1997, 2000, 2004, and 2006 (N = 3,591). Body mass index (BMI) was dichotomized as normal (18.5-24.9 kg/m(2)) and overweight (25.0-29.9 kg/m(2))/obese (≥30 kg/m(2)). Generalized estimating equations were used to estimate population-averaged (marginal) effects.

RESULTS

The combined prevalence of overweight or obese was approximately 33%. Moderate or heavy non-leisure physical activities (OR = 0.39; 95% CI = 0.32-0.49) and smoking (OR = 0.69; 95% CI = 0.57-0.84) decreased the odds of being overweight or obese, while drinking alcohol (OR = 1.25; 95% CI = 1.05-1.50) increased the odds. For individuals in all income levels, the amount of non-leisure physical activity strongly affected the BMI among the older Chinese adults.

CONCLUSIONS

Active lifestyle interventions may help counter what could otherwise be a growing obesity epidemic in China.

Lifetime Risk and Duration of Chronic Disease and Disability

Objective: To estimate risk and duration of chronic conditions and disability for all older Americans and demographic subgroups. Method: Analysis of National Mortality Followback Survey data for survivors to age 65 to project lifetime risk and duration of selected conditions and examine their relationship with life expectancy and disability. Results: For women, Blacks, and non-Blacks, arthritis is most common and has the longest average duration, followed by diabetes and COPD. Among men, diabetes duration is longest, followed by COPD. Disability risk is elevated for all conditions studied, except heart attack. Those very overweight most of life and persons with dementia have the greatest disability risk and relatively long disability durations. Among women, those very overweight most of life can expect to die 3.1 years sooner and have above average disability duration. Discussion: Findings provide new information about the relative burden of common chronic diseases among all older Americans and major subgroups.

Variations in Body Mass Index Among Older Americans: The Roles of Social and Lifestyle Factors

Objectives: To investigate the correlates of body mass index (BMI) among a national sample of older adults in the United States. Method: Data used in these analyses were part of the 2003-2004 National Health and Nutrition Examination Survey (NHANES). Generalized ordered logistic regression was used to analyze difference between normal weight, overweight, moderately obese, and severely obese adults ( n = 1,143) above the age of 65 years. Results: A higher BMI was more common among those with greater activities of daily living (ADL) limitations, greater use of prescription medicines (≥7), greater number of cardiovascular-related disorders (1 or ≥2), and those aged 65 to 74 years. Discussion: The findings acknowledge relationships between health characteristics, disability, and BMI among a national sample of older adults. These results suggest that prevention and management of health conditions, basic ADL, and BMI may be reasonable targets for intervention.

Chronic medical conditions and the sex-based disparity in disability: the Cardiovascular Health Study

BACKGROUND

Older women experience disability more commonly than their male peers. This disparity may be due, in part, to sex-based differences in the prevalence or the disabling effects of common medical conditions. The objectives of this analysis were to (a) quantify the extent to which excess disability in women is explained by higher prevalence of selected medical conditions and (b) evaluate whether the same conditions have differing effects on disability in men and women.

METHODS

We analyzed cross-sectional data from 5,888 community-dwelling older men and women. Disability was defined as difficulty with greater than or equal to one activity of daily living. Thirteen medical conditions were assessed by self-report, testing, or record review.

RESULTS

Controlling for age, race, education, and marital status, women were more likely to experience disability (odds ratio = 1.70, 95% confidence interval = 1.36-2.11). Higher prevalence of arthritis and obesity in women explained 30.2% and 12.9%, respectively, of the sex-based difference in disability rates, whereas male prevalent diseases like vascular conditions and emphysema narrowed the disability gap. Women with arthritis, hearing problems, coronary artery disease, congestive heart failure, stroke, and claudication were more likely to exhibit disability compared with men with the same conditions (p < .001).

CONCLUSIONS

Efforts to lessen sex-based inequality in disability should focus on reducing the prevalence of arthritis and obesity. Future generations may see greater functional disparity if rates of vascular disease and emphysema rise among women. Several conditions were more often associated with disability in women, suggesting additional sex-based differences in the disablement process.

Body mass index, disability, and 13-year mortality in older French adults

OBJECTIVE

To investigate the relationship between mortality and BMI in older people, taking into account other established mortality risk factors.

METHODS

A total of 3,646 French community dwellers aged 65 years and older from PAQUID cohort study were included. Cox proportional-hazards analysis was used to assess association between BMI and mortality.

RESULTS

Death occurred in 54.1% of the cohort more than 13 years: 68.99% of the underweight (BMI <19), 52.13% of the obese (BMI >30), 51.66% of the overweight (BMI 25-30), and 51.79% of the reference participants (BMI 22-25) died.The relative risk of death as a function of BMI, adjusted for gender and age, formed a U-shaped pattern, with larger risks associated with lower BMI (<22.0) and for BMI of 25.0 to 30.0 and BMI >/=30. (BMI 22.0-24.9 was the reference.) After adjustment for demographic factors, smoking history, and comorbidity, increased mortality risk persisted in underweight older people, BMI <18.5 and BMI 18.5-22 (respectively, HR = 1.45, 95% CI 1.17-1.78; HR = 1.27, 95% CI 1.12-1.43) compared with reference. Overweight (BMI 25-29.9) and obesity (>/=30) were not associated with increased mortality compared with the reference category (respectively, HR = 0.98, 95% IC 0.88-1.10; HR = 1.06, 95% IC 0.89-1.27). Similar relationships persisted for disabled participant. For nondisabled participant disability did not alter the associations for BMI of 25.0 and higher but for BMI less than 22.0, the risks become insignificantly different from those for the reference group.

DISCUSSION

BMI below 22 kg/ m(2) is a risk factor for 13-year mortality in older people, but our findings suggest that overweight and obesity may not be associated to mortality after adjustment for established mortality risk factors.

The effect of obesity combined with low muscle strength on decline in mobility in older persons: results from the InCHIANTI study

OBJECTIVE

Both obesity and muscle impairment are increasingly prevalent among older persons and negatively affect health and physical functioning. However, the combined effect of coexisting obesity and muscle impairment on physical function decline has been little studied. We examined whether obese persons with low muscle strength experience significantly greater declines in walking speed and mobility than persons with only obesity or low muscle strength.

DESIGN

Community-dwelling adults aged > or = 65 years (n = 930) living in the Chianti geographic area (Tuscany, Italy) were followed for 6 years in the population-based InCHIANTI study.

MEASUREMENTS

On the basis of baseline measurements (1998-2000), obesity was defined as body mass index (BMI) > or = 30 kg/m(2) and low muscle strength as lowest sex-specific tertile of knee extensor strength. Walking speed and self-reported mobility disability (ability to walk 400 m or climb one flight of stairs) were assessed at baseline and at 3- and 6-year follow-up.

RESULTS

At baseline, obese persons with low muscle strength had significantly lower walking speed compared with all other groups (P < or = 0.05). In longitudinal analyses, obese participants with low muscle strength had steeper decline in walking speed and high risk of developing new mobility disability over the 6-year follow-up compared with those without obesity or low muscle strength. After the age of 80, the differences between groups were substantially attenuated. The differences seen in walking speed across combination of low muscle strength and obesity groups were partly explained by 6-year changes in muscle strength, BMI and waist circumference.

CONCLUSIONS

Obesity combined with low muscle strength increases the risk of decline in walking speed and developing mobility disability, especially among persons < 80 years old.

Mexican Americans and frailty: findings from the Hispanic established populations epidemiologic studies of the elderly

OBJECTIVES

We examined the prevalence of frailty among Mexican American older adults and explored the correlates associated with becoming frail to determine their affect on disability and morbidity in this population.

METHODS

We studied the trajectory of frailty over 10 years in 2049 Mexican Americans participating in the Hispanic Established Populations Epidemiologic Studies of the Elderly. We constructed a frailty index based on weight loss, exhaustion, grip strength, walking speed, and physical activity and collected data on sociodemographic and health status, comorbidities, and functional measures of performance.

RESULTS

The sample was 58% female, with a mean age of 74.43 years (SD = 6.04) at baseline. Fifty-five percent of participants at baseline and 75% of the surviving sample at follow-up (n = 777) were classified as prefrail or frail. Of persons identified as frail at baseline, 84% died by the end of follow-up. Baseline age, diabetes, arthritis, smoking status, body mass index, cognition, negative affect, and number of comorbid conditions were predictors of frailty at follow-up (R(2) = 0.29; P < .05).

CONCLUSIONS

Further research into ways to reduce the number of Mexican American older adults who become frail and disabled and therefore lose their independence is needed. Future studies should continue to examine the trajectory of frailty as a dynamic process that includes psychosocial and cognitive components.

A framework for the concurrent consideration of occupational hazards and obesity

Occupational hazards and obesity can lead to extensive morbidity and mortality and put great financial burden on society. Historically, occupational hazards and obesity have been addressed as separate unrelated issues, but both are public health problems and there may be public health benefits from considering them together. This paper provides a framework for the concurrent consideration of occupational hazards and obesity. The framework consists of the following elements: (i) investigate the relationship between occupational hazards and obesity, (ii) explore the impact of occupational morbidity and mortality and obesity on workplace absence, disability, productivity and healthcare costs, (iii) assess the utility of the workplace as a venue for obesity prevention programs, (iv) promote a comprehensive approach to worker health and (v) identify and address the ethical, legal and social issues. Utilizing this framework may advance the efforts to address the major societal health problems of occupational hazards and obesity.

Recent declines in chronic disability in the elderly U.S. population: risk factors and future dynamics

As U.S. life expectancy has increased, questions arise as to how the quality of health and functioning in the elderly population has changed. Data from the 1982-2004 National Long-Term Care Survey (NLTCS) suggested that chronic disability prevalence above age 65 declined at an increasing rate with a 2.2% per annum rate of decline from 1999 to 2004 ( 71 ). Inflation-adjusted per capita Medicare expenditure rates in nondisabled persons also declined, 0.9% per annum from 1982 to 2004, which suggests that declines in disability were driven by improving health -- not by increases in per capita health expenditures. Declines in disability prevalence were found in other U.S. national health surveys. Analyses of U.S. Civil War veterans suggest recent disability declines were continuations of declines in both chronic disease and disability occurring over the past century due to improved nutrition, sanitation, and education. Concerns exist about whether disability declines will continue because of recent increases in obesity prevalence.

Ethnic differences in dairy and related nutrient consumption among US adults and their association with obesity, central obesity, and the metabolic syndrome

BACKGROUND

Recent studies suggest dairy consumption and associated nutrients may be protective against some of the components of the metabolic syndrome (MetS).

OBJECTIVES

We examined the association between consumption of a variety of dairy products and their related nutrients with obesity, central obesity, and MetS, and attempted to explain some of the ethnic differences in metabolic outcomes through dairy consumption using national data.

DESIGN

Nationally representative indicators of obesity, central obesity, and MetS among US adults were constructed from National Health and Nutrition Examination Survey 1999-2004 data, including direct anthropometric assessments, blood pressure, and laboratory tests. Sample sizes ranged from 4519 for MetS to 14 618 for obesity. Associations between diet (assessed using 24-h recalls) and metabolic and other outcomes were tested using multivariate linear and logistic models and structural equation models.

RESULTS

We found a significant inverse association between intake of whole milk, yogurt, calcium, and magnesium and metabolic disorders. Odds ratios for one more daily serving of yogurt and 100 mg Mg for MetS were 0.40 (95% CI: 0.18, 0.89) and 0.83 (95% CI: 0.72, 0.96), respectively. The opposite was found for intakes of cheese, low-fat milk, and phosphorus. Using structural equation models, ethnic differences in some MetS outcomes, such as body mass index and systolic blood pressure, were partly explained by variations in dairy-related nutrients.

CONCLUSIONS

Various dairy products may have differential associations with metabolic disorders, including obesity. Ethnic differences in dairy consumption may explain in part the ethnic disparities in metabolic disorders in the US population.