Self-Reported Concern About Food Security Associated with Obesity --- Washington, 1995--1999

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Obesity is epidemic among all segments of the U.S. population and in all regions of the country, and persons who are obese are at higher risk for several chronic diseases (1). Previous studies have suggested a possible relation between obesity and food insecurity (i.e., not having access at all times to enough safe and nutritious food for an active, healthy lifestyle [2] because such foods are not available consistently or household resources are insufficient to meet the cost) (3--5). To assess the relation between obesity and concern about food security, the Washington state Department of Health analyzed statewide data from the 1995--1999 Behavioral Risk Factor Surveillance System (BRFSS). This report summarizes the results of the analysis, which indicate that concern about food security is associated with obesity. Longitudinal studies are needed to determine whether food insecurity causes obesity so appropriate interventions can be designed and implemented.

BRFSS is an ongoing, random-digit--dialed telephone survey of the U.S. civilian, noninstitutionalized population aged >18 years. The state-based survey collects data about modifiable risk factors for chronic diseases and leading causes of death. During 1995--1999, a total of 17,371 persons responded to the Washington BRFSS (median response rate: 52.4%; range: 50.2%--61.5%). The survey collected self-reported data on height and weight that were used to calculate body mass index (BMI) (i.e., weight in kilograms divided by height in meters squared [weight (kg)/height squared (m²)]). Obesity was defined as having BMI of >30.0 kg/m². Having concerns about food security was defined as answering "yes" to the question, "In the past 30 days, have you been concerned about having enough food for you or your family?" Each potential risk factor was analyzed separately by using simple logistic regression to identify risk factors for obesity. Multiple logistic regressions were conducted to identify risk factors for obesity while controlling for potential confounders. SUDAAN was used to account for the complex sampling design.

During 1995–1999, of 17,371 respondents, 3,252 (18.7%) were classified as obese. Persons who reported concern about food security, whose annual household income was <$20,000, who had no college education, or who were female, black, American Indian/Alaska Native, Hispanic, or aged >45 years were more likely to be obese than other persons (Table). Asians/Pacific Islanders were less likely be obese than whites. Obese persons also were more likely to report a sedentary lifestyle, to eat fewer fruits and vegetables, to have poorer health, and to have received a diagnosis of asthma. Because no significant interactions were found among the independent variables, only the main-effect variables were included in the model. Although reporting poor or fair health status and having received a previous diagnosis of asthma were associated with obesity in the simple logistic regression analyses, these conditions were not included in the multiple regression model because they probably result from rather than cause obesity (6).

The multiple logistic regression model included income and education as potential confounders. Persons who reported concern about food security were more likely to be obese than those who did not report such concerns (adjusted odds ratio = 1.29; 95% confidence interval = 1.04–1.83 (Table).

Reported by: J VanEenwyk, PhD, Washington State Dept of Health. J Sabel, PhD, EIS Officer, CDC.

Editorial Note: Both obesity and food insecurity are increasing in the United States (1,7). Previously identified risk factors for obesity among adults include having a low income (among women) or education level, being aged >45 years or a member of certain racial/ethnic populations, and not being active physically or eating the recommended amount of fruits and vegetables daily (1). This report supports the findings of previous studies that food insecurity is associated with obesity (3–5).

Possible explanations for the association between food insecurity and obesity include periods of both under- and overconsumption, physiologic adaptation of increased body fat in response to episodic food shortages, and higher consumption of cheaper foods that are higher in fat (5). For example, diets of food-insecure women include fewer fruits and vegetables (3). Studies of dieters, prisoners of war, and children with food-restrictive parents indicate that food deprivation can lead to overconsumption of foods restricted previously after the restriction ends (5).

The findings in this report are subject to at least five limitations. First, self-reported data are subject to recall bias and inaccurate reporting of behaviors. Persons who are obese tend to underreport their weight (8). Second, the data might not be generalizable to the entire population. Third, these data are cross-sectional, which limits the ability to draw conclusions about cause and effect. Fourth, the number of food-insecure persons might be underestimated because such persons might be less likely to have telephones. Finally, the question used to assess concern about food security has not been tested for reliability or validity. However, patterns of concern about food security and income as determined from one question (9) are consistent with patterns identified from surveys using more questions to determine food security (10).

Further longitudinal research is needed to determine whether food insecurity causes obesity. If such a relation were to be demonstrated, interventions to reduce food insecurity might reduce the burden of obesity in the United States.

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