Interaction between unhealthy sleep pattern and obesity on cardiometabolic multimorbidity

Obesity and unhealthy sleep are established risk factors for cardiometabolic multimorbidity, but their joint effect remains unclear. This study aims to investigate their joint effect on cardiometabolic multimorbidity risk by analyzing data from 2 independent cohorts.

We analyzed cross-sectional (Fuqing Cohort, N = 34,703) and prospective data (UK Biobank, N = 362,474; 12.3-year median follow-up, 3980 incident cardiometabolic multimorbidity cases). We defined unhealthy sleep (≥3 of 5 traits: late chronotype, sleep <7 or >8 h/day, frequent insomnia symptoms, self-reported snoring, frequent daytime sleepiness), cardiometabolic multimorbidity (≥2 of type 2 diabetes, coronary heart disease, stroke), and obesity (general: BMI ≥25 kg/m²; central: waist circumference ≥80 cm in women, ≥94/90 cm in European/Asian men). The reference group had a sleep score <3 and no corresponding obesity. Logistic and Cox regressions evaluated associations and additive interaction was assessed.

Unhealthy sleep and both obesity types independently increased cardiometabolic multimorbidity risk in both populations. The joint effect was stronger for unhealthy sleep combined with central obesity (FQC adjusted OR = 3.46; UKB adjusted HR = 2.55) than general overweight/obesity (FQC adjusted OR = 2.61; UKB adjusted HR = 2.46). Additive interaction showed stronger effect for unhealthy sleep with central versus general overweight/obesity in Europeans (adjusted RERI: 0.61 vs. 0.32). A similar additive interaction in Asians turned non-significant after covariate adjustment. Insomnia and central obesity showed a significant additive interaction in both cohorts.

Unhealthy sleep and obesity jointly increase cardiometabolic multimorbidity risk, with central obesity having a stronger additive interaction than general overweight/obesity. Integrated public health strategies targeting sleep and weight are warranted.