Angela G. Fowler-Brown

Objective: Obesity is associated with an increased risk of osteoarthritis (OA) of the knee. Emerging evidence suggests that adipokines, substances produced by adipose tissue, may play a role in the development of knee OA. The aim of this study was to determine whether the inflammatory adipokine leptin partially mediates the relationship between body mass index (BMI) and knee OA.Methods: We used baseline data from 653 participants who were 70 years of age or older in the population‐based Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly Boston Study. Height and weight were measured, and participants were assessed for knee OA using clinical criteria. Serum leptin was measured using a microsphere‐based assay.Results: The average BMI and the average serum leptin level were 27.5 kg/m² and 589 pM, respectively; the prevalence of knee OA was 24.7%. In regression models adjusted for covariates, we found that a 5‐kg/m² increase in BMI was associated with 32% increased odds of knee OA (odds ratio [OR] 1.32, 95% confidence interval [95% CI] 1.10, 1.58); a 200‐pM increase in serum leptin levels was associated with 11% increased odds of knee OA (OR 1.11, 95% CI 1.05, 1.17). The ratio of the standardized coefficients for the indirect:total effect calculated using the product‐of‐coefficients method was 0.49, suggesting that approximately half of the total effect of BMI on knee OA may be mediated by serum leptin. The estimated 95% CIs for the mediated effect suggest that this effect is statistically significant. Similarly, mediation analysis using a counterfactual approach suggested that the effect of leptin mediation was statistically significant.Conclusion: We found that almost half of the association between elevated BMI and knee OA could be explained by the inflammatory adipokine leptin.

Objectives: To determine the extent to which bodily pain mediates the effect of obesity on disability and physical function. Design: Cross‐sectional analysis. Setting: Population‐based sample of residents in the greater Boston area. Participants: Community‐dwelling adults aged 70 and older (N = 736). Measurements: Body mass index ( BMI ), obtained from measured height and weight, was categorized as normal weight (19.0–24.9 kg/m ² ), overweight (25.0–29.9 kg/m ² ), or obese (≥30.0 kg/m ² ). Main outcome measures were the P hysical C omponent S ummary of the M edical O utcomes S tudy 12‐item S hort‐ F orm S urvey ( PCS ), activity of daily living ( ADL ) disability, and S hort P hysical P erformance B attery ( SPPB ) score. Chronic pain was assessed according to the number of weight‐bearing joint sites that had pain (hips, knees, feet and pain all over). Results: Older obese adults had greater ADL disability and lower SPPB and PCS scores than their nonobese counterparts, although in sex‐stratified adjusted analyses, obesity was adversely associated with outcomes only in women. Obesity was associated with greater number of pain sites; and more pain sites were associated with greater odds of disability. Mediation analysis suggests that pain is a significant mediator (22–44%) of the adverse effect of obesity on disability and physical function in women. Conclusion: Bodily pain may be an important treatable mediator of the adverse effect of obesity on disability and physical function in women.

A bidirectional relationship between obesity and depression may exist, though previous results are conflicting. The objectives of our study were to determine whether there is a bidirectional relationship between obesity and symptoms of depression in younger adults and whether this relationship varies with sociodemographic factors. We used data from 7,980 participants in the National Longitudinal Survey of Youth 1979 to examine whether baseline depressive symptoms (score ≥ 10 on a seven‐item subscale of the CES‐D) in 1992, predicted adjusted percent change in BMI between 1992 and 1994. We then examined whether obesity in 1992 predicted the development of symptoms of depression in 1994, after adjustment for confounders. We found that the presence of baseline depressive symptoms was not prospectively associated with increase in percent BMI, except in Hispanic women. Additionally, baseline obesity was not associated with higher risk of future symptoms of depression in the sample overall (adjusted risk ratio (RR) 1.20; 99% CI 0.91–1.60). However, in those of higher socioeconomic status, obesity was associated with almost double the risk of depressive symptoms compared to nonobese (highest income category: adjusted RR 1.97; 99% CI 1.14–3.40). We concluded that although obesity was not associated with risk of depression symptoms in the population overall, obesity was associated with an increased risk of developing depressive symptoms in those of higher socioeconomic status. Sociodemographic factors may be important modifiers of the relationship between obesity and depression.

The current impact of adolescent obesity on educational attainment is not clear. The objectives of our study were to determine whether adolescent obesity is associated with college degree attainment and how this association may have changed over time. We used data from a contemporary national cohort of over 4,000 persons who were adolescents (aged 14–18) in 1997 to assess the relationship between adolescent obesity and education. To assess for changes in this relationship over time, we also analyzed an older, similarly structured cohort of over 3,000 persons who were adolescents (aged 16–18) in 1981. Our primary outcome was college degree completion. We found that in the older cohort (adolescents in 1979), there were no differences in college degree attainment by adolescent weight status before and after adjustment. However, unadjusted analysis of the contemporary cohort (adolescents in 1997) demonstrated that those who were normal weight as adolescents had a higher prevalence of college degree attainment at follow‐up compared to obese adolescents (24% vs. 10%). After adjustment for socio‐demographic variables (age, sex, race, height, parental income‐to‐poverty ratio, parental education, aptitude test scores), obese adolescents were less likely to have attained a college degree compared to normal weight peers (adjusted risk ratio 0.61 95% confidence interval 0.38–0.83). Expectations for a future college degree did not vary by weight status and did not explain this observation. In conclusion, adolescent obesity is associated with lower likelihood of college completion. This relationship was not observed in an older cohort of adolescents.

OBJECTIVE: To examine the relationship of parity with diabetes and markers of glucose homeostasis in older women. RESEARCH DESIGN AND METHODS: We used data from the female participants in the Cardiovascular Health Study, a longitudinal cohort of adults aged ≥65 years. These data included an assessment of parity (baseline) and fasting serum levels of glucose, insulin, and medication use (baseline and follow-up). We estimated both the cross-sectional relationship of parity with baseline diabetes and the relationship of parity with incident diabetes. RESULTS: In unadjusted analyses, women with grand multiparity (≥5 live births) had a higher prevalence of diabetes at baseline compared with those with fewer births and with nulliparous women (25 vs. 12 vs. 15%; P < 0.001). In regression models controlling for age and race, grand multiparity was associated with increased prevalence of diabetes (prevalence ratio 1.57 [95% CI 1.20–2.06]); with addition of demographic and clinical factors to the model, the association was attenuated (1.33 [1.00–1.77]). In final models that included body anthropometrics, the association was no longer significant (1.21 [0.86–1.49]). In those without diabetes at baseline, parity was not associated with incident diabetes or with fasting glucose; however, there was a modest association of parity with fasting insulin and homeostasis assessment model of insulin resistance. CONCLUSIONS: Grand multiparity is associated with diabetes in elderly women in cross-sectional analyses. This relationship seems to be confounded and/or mediated by variation in body weight and sociodemographic factors by parity status. In older nondiabetic women, higher parity does not pose an ongoing risk of developing diabetes.

Adverse psychosocial exposures may partially drive the high rates of obesity among blacks. The objective of this study was to prospectively examine the relationship between perceived psychosocial stress and percent change in BMI among adult black men and women. We used data from 756 women and 416 men who were participants in the Pitt County Study, a community‐based, prospective cohort study of blacks in eastern North Carolina. Participants were aged 25–50 years of age on entry into the study in 1988 and follow‐up was obtained in 2001. Using multivariable linear regression, we calculated the adjusted mean percentage change in BMI over the follow‐up period for each tertile of baseline measures of the Perceived Stress Scale (low, medium, and high), adjusted for potential confounders. For black women, higher levels of psychosocial stress at baseline predicted higher adjusted percentage increase in BMI over the 13‐year follow‐up: low stress 12.0% (95% CI 9.6–14.4), medium stress 16.3% (95% CI 13.7–18.9), and high stress 15.5% (95% CI 13.1–17.8). For black men, perceived stress was not associated with percent BMI change. These data suggest that interventions targeting obesity in black women should consider the potential impact of emotional stress on weight change.

Many Americans lack health insurance. Despite good evidence that lack of insurance compromises access to care, few prospective studies examine its relationship to health outcomes. To determine the relationship between insurance and cardiovascular outcomes and the relationship between insurance and selected process measures. We used data from 15,792 participants in the Atherosclerosis Risk in Communities Study, a prospective cohort study. Participants were enrolled in 1987–1989 and returned for follow-up visits every 3 years, for a total of 4 visits. We estimated the hazard of myocardial infarction, stroke, and death associated with insurance status using Cox proportional hazard modeling. We used generalized estimating equations to examine the association between insurance status and risk of (1) reporting no routine physical examinations, (2) being unaware of a personal cardiovascular risk condition, and (3) inadequate control of cardiovascular risk conditions. Persons without insurance had higher rates of stroke (adjusted hazard ratio, 95% CI 1.22–2.22) and death (adjusted hazard ratio 1.26, 95% CI 1.03–1.53), but not myocardial infarction, than those who were insured. The uninsured were less likely to report routine physical examinations (adjusted risk ratio 1.13, 95% CI 1.08–1.18); more likely to be unaware of hypertension (adjusted risk ratio 1.12, 95% CI 1.00–1.25) and hyperlipidemia (adjusted risk ratio 1.11, 95% CI 1.03–1.19); and more likely to have poor blood pressure control (adjusted risk ratio 1.23, 95% CI 1.08–1.39). Lack of health insurance is associated with increased rates of stroke and death and with less awareness and control of cardiovascular risk conditions. Health insurance may improve cardiovascular risk factor awareness, control and outcomes.

We assessed how commonly people in the rural South perceive racial barriers to care, the characteristics of the people among whom this perception is most common and whether this perception is associated with satisfaction with and use of health services. We analyzed telephone survey data collected in 2002–3, using weighted statistical techniques and multivariate logistic regression in analyses stratified by race. Fifty-four percent of African Americans and 23% of Whites reported that they perceive racial barriers to care in their communities. African Americans who were middle-aged or older, male, or who report being in good-to-excellent health were more likely to perceive racial barriers. Whites who were younger, less educated, and uninsured were more likely than other Whites to perceive racial barriers. For African Americans, perceptions of racial barriers were associated with lower likelihood of being satisfied with care, but not with use of preventive services. The perception of racial barriers to health care is prevalent in the rural South, especially among African Americans. The consequences of this perception may include mistrust and dissatisfaction with medical care.