A prospective study of frequency of eating restaurant prepared meals and subsequent 9-year risk of all-cause and cardiometabolic mortality in US adults

Restaurant prepared foods are known to be energy-dense and high in fat and sodium, but lower in protective nutrients. There is evidence of higher risk of adiposity, type II diabetes, and heart disease in frequent consumers of restaurant meals. However, the risk of mortality as a long-term health consequence of frequent consumption of restaurant meals has not been examined. We examined the prospective risk of all-cause and coronary heart disease, cerebrovascular disease and diabetes (cardiometabolic) mortality in relation to frequency of eating restaurant prepared meals in a national cohort. We used frequency of eating restaurant prepared meals information collected in the National Health and Nutrition Examination Surveys, conducted from 1999-2004, with mortality follow-up completed through Dec. 31, 2011 (baseline age >= 40y; n = 9107). We estimated the relative hazard of all-cause and cardiometabolic mortality associated with weekly frequency of eating restaurant meals using Cox-proportional hazards regression methods to adjust for multiple covariates. All analyses accounted for complex survey design and included sample weights. Over 33% of all respondents reported eating >= 3 restaurant prepared meals/week. In this cohort, 2200 deaths due to all causes and 665 cardiometabolic deaths occurred over a median follow-up of 9 years. The covariate-adjusted hazard ratio of all cause or cardiometabolic mortality in men and women reporters of <1 or 1-2 restaurant prepared meals did not differ from those reporting >= 3 meals/week (P>0.05). The results were robust to effect modification by baseline BMI, years of education, and baseline morbidity. Expectedly, the 24-h dietary intakes of whole grains, fruits, dietary fiber, folate, vitamin C, potassium and magnesium at baseline were lower, but energy, energy density, and energy from fat were higher in more frequent restaurant meal reporters (P<0.05). Baseline serum HDL cholesterol, folate, and some carotenoids were inversely associated with the frequency of eating restaurant prepared meals (P<0.05); however, serum concentrations of total cholesterol, triglycerides, fasting glucose, insulin, glycated hemoglobin, and c-reactive protein were unrelated (P<0.05). The weekly frequency of eating restaurant prepared meals and prospective risk of mortality after 9 years were not related in this cohort.