Association between nutrition and weight status and mortality among adults: A cross-sectional study

The impact of malnutrition coexisting with obesity on mortality risk in community-dwelling adults remains incompletely understood. This study aimed to examine the individual and combined effects of malnutrition and obesity on the risk of all-cause and cardiovascular disease (CVD) mortality in US adults.

We performed a cross-sectional study examining the association between malnutrition and obesity, as measured by the Controlling Nutritional Status score and body mass index, with all-cause and CVD mortality in 28,202 adults using data from the 1999-2018 National Health and Nutrition Examination Survey. Participants were categorized into four groups: nourished and nonobese, nourished and obese, malnourished and nonobese, and malnourished and obese.

The prevalence of any degrees of malnutrition and moderate-to-severe malnutrition were 14.03% and 0.16%, respectively. During a median follow-up time of 123 months, 6.19% participants died, of which 28.05% were CVD deaths. Compared with the reference group, the hazard ratios (HRs) of all-cause mortality were 1.58 (95% confidence interval [CI], 1.34-1.86) for the malnourished and nonobese group, 1.03 (95% CI, 0.91-1.16) for the nourished and obese group, and 1.30 (95% CI, 1.06-1.59) for the malnourished and obese group. The HRs of CVD mortality were 1.61 (95% CI, 1.21-2.14) for the malnourished and nonobese group, 1.23 (95% CI, 0.98-1.55) for the nourished and obese group, and 2.09 (95% CI, 1.41-3.10) for the malnourished and obese group.

Malnutrition increases mortality risk regardless of weight status, highlighting the importance of nutrition assessment even in individuals with obesity.