Obesity in minority populations: an epidemiologic assessment

This article reviews issues relating to the prevalence, health implications, and prevention and treatment perspectives of obesity in U.S racial and ethnic minority groups. The growing interest in obesity in minority populations reflects an awareness of the high prevalence of obesity among black, Hispanic, Asian and Pacific Islander and Native Americans as well as a generally increased interest in minority health. In addition, the fact that some aspects of obesity among minorities differ from those in whites suggests that new insights may be gained from studying obesity in diverse populations. However, there are many methodological problems to be overcome, including some that arise from the way minority groups are defined. Under the assumption that all obesity results from a period of sustained positive energy balance at the individual level, an epidemiologic explanation for the excess of obesity in minorities at the population level seems readily apparent. A surplus of obesity-promoting forces and a deficit of obesity-inhibiting forces, caused by secular changes in food availability and physical activity, accompany the early phases of modernization and economic advancement. The high prevalence of obesity in minority populations can be viewed as a function of the slope and timing of these secular changes. Genetic predisposition, cultural attitudes, and exposure to maternal obesity and diabetes in utero may be potentiating factors. In this context, interventions targeting individuals would seem inevitably to put racial and ethnic minority groups on the path toward the same weight control crisis now observed in the majority white population. This suggests that the underlying causes of the societal energy balance problem must be addressed at the population level in order for effective clinical approaches to be developed for minority populations with a high obesity prevalence.     

Outcomes of a cardiovascular nutrition counseling program in African-Americans with elevated blood pressure or cholesterol level

OBJECTIVE: To evaluate a cardiovascular nutrition education package designed for African-American adults with a wide range of literacy skills. DESIGN: Comparison of a self-help group and a full-instruction group; each group received nutrition counseling and clinical monitoring every 4 months. SUBJECTS: Three hundred thirty African-American adults, aged 40 to 70 years, with elevated cholesterol level or high blood pressure were randomly assigned to the self-help or full-instruction group; 255 completed the 12-month follow-up. INTERVENTIONS: Counseling to reduce intake of dietary fat, cholesterol, and sodium was based on Cardiovascular Dietary Education System (CARDES) materials, which included food-picture cards, a nutrition guide (self-help and full-instruction group), a video and audiotape series, and 4 classes (full-instruction group only). MAIN OUTCOME MEASURES: Changes in lipid levels and blood pressure after 12 months. STATISTICAL ANALYSES PERFORMED: Primary analyses consisted of repeated-measures analysis of variance to examine effects of time and randomization group on outcomes. RESULTS: Total cholesterol and low-density lipoprotein cholesterol level decreased by 7% to 8% in the self-help and full-instruction groups of men and women (P < .01). The ratio of total cholesterol to high-density lipoprotein cholesterol (HDL-C) decreased in both groups of women and in the men in the full-instruction group (P < .01). In full-instruction and self-help participants with elevated blood pressure at baseline, systolic blood pressure decreased by 7 to 11 mm Hg and diastolic blood pressure decreased by 4 to 7 mm Hg (P < .01). Outcomes did not differ by literacy scores but were positively related to the reported initial frequency of using CARDES materials. APPLICATIONS/CONCLUSIONS: These results suggest that periodic nutrition counseling based on CARDES materials used for home study can enhance management of lipid levels and blood pressure in African-American outpatients.     

Relative validity of food frequency questionnaire nutrient estimates in the Black Women's Health Study

PURPOSE: The Black Women's Health Study (BWHS) was designed to investigate determinants of health and disease in US black women. More than 64,000 women are enrolled in the BWHS cohort. This study assessed the relative validity of the 68-item food frequency questionnaire (FFQ) used in the BWHS baseline questionnaire. METHODS: Four hundred and eight BWHS enrollees were asked to provide three telephone, 24-hour recalls and one written 3-day food diary over a one-year period. Means and Pearson correlations were computed to compare estimates for energy, total fat, saturated fat, protein, carbohydrate, dietary fiber, calcium, iron, vitamin C, folate, beta-carotene, and vitamin E from the FFQ, recalls, and diaries. RESULTS: Mean energy intake (kcal) was higher for the diary (1716) than the FFQ (1601) or recalls (1510). Other nutrient estimates (% kcal or per 1000 kcal) were similar across methods, except beta-carotene (FFQ higher). Correlations (energy-adjusted, except for energy, and corrected for intraperson variation) between the FFQ and the recalls were higher than for the diary data and were between 0.5 and 0.8, except for energy and vitamin E (both <0.3). CONCLUSION: The BWHS FFQ will support meaningful analyses of diet-health associations for 10 of the 11 energy-adjusted nutrient intake variables analyzed.     

Confidence of health professionals in public health approaches to obesity prevention.

OBJECTIVE: To assess the views of professionals working in the obesity field on the potential usefulness and feasibility of implementing different types of public health prevention strategies. METHOD: A questionnaire listing 20 public health strategies was mailed to pre-registrants of an international obesity prevention symposium. Respondents were asked to rate how useful and how feasible they felt each of the listed actions would be for the prevention of obesity in their home countries. The list included education-based strategies aimed at changing individual behaviour as well as more radical measures aimed at reducing population exposure to obesity-promoting factors in the environment. RESULTS: A 32% response was obtained. Education-based strategies were seen to be both useful and feasible. Less confidence was expressed in strategies aimed at changing the environment. CONCLUSION: People working in the obesity field tend to feel most comfortable with education-based prevention strategies. Implementation of environment-based strategies needed to encourage and support behaviour change may require the involvement of people from relevant sectors outside the obesity field.     

Body weight as a risk factor in the elderly

To determine whether body weight is a risk factor for mortality among older persons, we analyzed body mass index (weight [kilogram]/height [square meter]) data for 4710 white, National Health and Nutrition Examination Survey respondents who were aged 55 to 74 years during 1971 through 1975, in relation to their survival over an average of 8.7 years of follow-up. In a multivariate analysis that controlled for elevated blood pressure, smoking, and poverty, we found no additional risk associated with weight among women and a statistically significant, but moderate, additional risk (relative risk, 1.1 to 1.2) among men in the upper decile (body mass index, greater than or equal to 30 kg/m2). In contrast, low weight (body mass index, less than 22 kg/m2) was associated with increased mortality (relative risk, 1.3 to 1.6) except for women aged 55 to 64 years. We conclude that the accepted definition of overweight (body mass index, greater than or equal to 27.8 kg/m2 [men] or greater than or equal to 27.3 kg/m2 [women]) lacks specificity and may be inappropriate for older persons who do not have weight-related medical conditions. The low-weight mortality association, consistently demonstrated, deserves serious scrutiny.