Abstract
Background: Body mass index (BMI) is closely linked to hypertension and diabetes mellitus (DM). However, the association between BMI and hypertension-diabetes comorbidity in elderly population of China remains uncertain.
Methods: This cohort study was conducted based on a prospective database of Chinese Longitudinal Healthy Longevity Survey (CLHLS). The primary outcome was hypertension-diabetes comorbidity. The secondary outcomes included hypertension and DM. BMI was categorized into four groups according to Chinese guidelines: underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5–23.9 kg/m2), overweight (BMI 24.0–27.9 kg/m2), and obesity (BMI ≥ 28.0 kg/m2).
Results: The final analysis included 5,342 individuals for hypertension, 6,335 for DM, and 6,414 for hypertension-diabetes comorbidity (all individuals aged 65 years and above). Cox regression analysis of the hypertension-diabetes comorbidity revealed the adjusted hazard ratio (HR) for the underweight group was 0.747 (95% confidence interval [CI], 0.651–0.857), for the overweight group was 1.517 (95% CI, 1.309–1.758), and for the obesity group was 1.620 (95% CI, 1.237–2.121) comparing with normal weight group (reference). When considering BMI as a continuous variable, the adjusted HR was 1.043 (95% CI, 1.029–1.059). Employing a multi-model adjusting strategy based on the directed acyclic graph, the HR for individuals with BMI ≥ 24.0 (versus BMI < 24.0) was 1.486 (95% CI, 1.301–1.698). Restricted cubic splines indicate a positive linear trend between BMI (range in BMI ≥ 24) and the risk of hypertension-diabetes comorbidity. The relationship between BMI and secondary outcomes exhibited results similar to those of the primary outcome.
Additionally, compared to the Han ethnic, other ethnic had a significantly lower risk of the primary outcome, with an adjusted HR of 0.334 (95% CI, 0.235–0.475). Similar findings were observed for the secondary outcomes.
Conclusions: Increased BMI is significantly associated with a higher risk of hypertension-diabetes comorbidity, hypertension, and DM in elderly population of China. Additionally, Han participants (versus non-Han) have a notably greater risk of developing hypertension-diabetes comorbidity, hypertension, and DM. Greater attention should be paid to obesity in elderly Han Chinese individuals, given its significant associated disease burden.