Body mass index and multimorbidity risk: A systematic review and dose-response meta-analysis

To verify the dose-response relationship between body mass index (BMI) and multimorbidity risk.

PubMed, CINAHL, and Embase were systematically studied until January 25, 2023. Original articles on BMI and multimorbidity risk were included. Random effects model and dose-response meta-analysis were used to estimate the pooled odds ratio (OR) with 95 % confidence interval (CI). Subgroup analysis was performed to explore potential heterogeneity.

A total of 43 studies involving 969,130 patients (94,978 with multimorbidity) were involved in the meta-analysis. In the longitudinal studies, the pooled results showed that, compared to being a normal BMI, being overweight was much similar with 1.32 times possibility of getting multimorbidity; in persons with obesity the risk was 1.93 times higher; and the risk decreased 0.80 times among underweight persons. Additionally, obesity was 1.75 times as likely to be multimorbidity than those non-obese persons. In the cross-sectional studies, the pooled results demonstrated that persons with overweight and obesity had a 1.38-fold and 2.38-fold risk for multimorbidity, respectively; and the risk decreased 0.90 times among underweight persons compared to those with normal BMI. Besides, obese people are 1.89 times more likely to have multimorbidity than non-obese people. Dose response analysis found the linear connection between BMI and multimorbidity risk (P_{non-linearity}=0.762), that for each 1 kg/m² and 5 kg/m² increase in BMI, the multimorbidity risk increased by 6 % and 35 %, respectively.

Multimorbidity increased linearly with an increase in BMI. Clinicians should pay attention to persons with abnormal weight, to help them achieve normal BMI.