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Objective: To investigate plausible contributors to the obesity epidemic beyond the two most commonly suggested factors, reduced physical activity and food marketing practices. Design: A narrative review of data and published materials that provide evidence of the role of additional putative factors in contributing to the increasing prevalence of obesity. Data: Information was drawn from ecological and epidemiological studies of humans, animal studies and studies addressing physiological mechanisms, when available. Results: For at least 10 putative additional explanations for the increased prevalence of obesity over the recent decades, we found supportive (although not conclusive) evidence that in many cases is as compelling as the evidence for more commonly discussed putative explanations. Conclusion: Undue attention has been devoted to reduced physical activity and food marketing practices as postulated causes for increases in the prevalence of obesity, leading to neglect of other plausible mechanisms and well-intentioned, but potentially ill-founded proposals for reducing obesity rates.

Background Dramatic increases in patients requiring linkage to HIV treatment are anticipated in response to updated CDC HIV testing recommendations advocating routine, opt-out testing. Methods A retrospective analysis nested within a prospective HIV clinical cohort study evaluated patients establishing initial outpatient HIV treatment at the University of Alabama at Birmingham 1917 HIV/AIDS Clinic between 1 January 2000 and 31 December 2005. Survival methods were used to evaluate the impact of missed visits in the first year of care on subsequent mortality in the context of other baseline sociodemographic, psychosocial, and clinical factors. Mortality was ascertained by query of the Social Security Death Index as of 1 August 2007. Results Among 543 study participants initiating outpatient HIV care, 60% missed a visit in the first year. Mortality was 2.3 per 100 person-years for patients who missed visits compared with 1.0 per 100 person-years for those who attended all scheduled appointments during the first year after establishing outpatient treatment (P=0.02). In Cox proportional hazards analysis, higher hazards of death were independently associated with missed visits (HR=2.90, 95%CI=1.28–6.56), older age (HR=1.58 per 10 years, 95%CI=1.12–2.22), and baseline CD4 count <200 cells/mm3 (HR=2.70, 95%CI=1.00–7.30). Conclusions Patients who missed visits in the first year after initiating outpatient HIV treatment had more than twice the rate of long-term mortality relative to those who attended all scheduled appointments. We posit that early missed visits are not causally responsible for the higher observed mortality, but rather identify patients more likely to exhibit health behaviors that portend increased subsequent mortality.

Objective. The frequency of many adverse events (AEs) associated with low-dose glucocorticoid use is unclear. We sought to determine the prevalence of glucocorticoid-associated AEs in a large US managed care population. Methods. Using linked administrative and pharmacy claims, adults receiving >60 days of glucocorticoids were identified. These individuals were surveyed about glucocorticoid use and symptoms of 8 AEs commonly attributed to glucocorticoid use. Results. Of the 6,517 eligible glucocorticoid users identified, 2,446 (38%) returned the mailed survey. Respondents were 29% men with a mean ؎ SD age of 53 ؎ 14 years; 79% were white and 13% were African American. Respondents had a mean ؎ SD of 7 ؎ 3 comorbid conditions and were prescribed a mean ؎ SD prednisone-equivalent dosage of 16 ؎ 14 mg/day. More than 90% of individuals reported at least 1 AE associated with glucocorticoid use; 55% reported that at least 1 AE was very bothersome. Weight gain was the most common self-reported AE (70% of the individuals), cataracts (15%) and fractures (12%) were among the most serious. After multivariable adjustment, all AEs demonstrated a strong dose-dependent association with cumulative glucocorticoid use. Among users of low-dose therapy (<7.5 mg of prednisone per day), increasing duration of use was significantly associated with acne, skin bruising, weight gain, and cataracts. Conclusion. The prevalence of 8 commonly attributed self-reported glucocorticoid-associated AEs was significantly associated with cumulative and average glucocorticoid dose in a dose-dependent fashion. Physicians should be vigilant for glucocorticoid-related AEs and should counsel patients about possible risks, even among low-dose long-term users.

Odds ratio (OR), risk ratio (RR), and prevalence ratio (PR) are some of the measures of association which are often reported in research studies quantifying the relationship between an independent variable and the outcome of interest. There has been much debate on the issue of which measure is appropriate to report depending on the study design. However, the literature on selecting a particular category of the outcome to be modeled and/or change in reference group for categorical independent variables and the effect on statistical significance, although known, is scantly discussed nor published with examples. In this article, we provide an example of a cross-sectional study wherein PR was chosen over (Prevalence) OR and demonstrate the analytic implications of the choice of category to be modeled and choice of reference level for independent variables.