Socioeconomic inequalities in cardiovascular risks among mid-aged and older Chinese: A nationally representative longitudinal study

Abstract

Background China is the fastest ageing nation and will become the world's most ageing society by 2030. Cardiovascular disease (CVD) remains the leading cause of mortality in China and ageing further complicate the picture of CVD profile in China. This study aims to examine socioeconomic disparities in cardiovascular risks among mid-aged and older Chinese. Methods Data were from 2011 baseline survey of China Health and Retirement Survey (CHALRS), which is a nationally representative longitudinal study of persons in China 45-years-older and their spouses. A sample of 12749 ≥ 45 years (male: n = 5968, mean age = 58.85; female: n = 6791, mean age = 58.35) were included in this paper. This paper concerns four CVD risk factors: systolic blood pressure, diastolic blood pressure, BMI and waist circumference. Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mmHg, and/or diastolic blood pressure (DBP) ≥ 90 mmHg. Overweight (and obesity) was defined as a BMI ≥ 24. Abdominal obesity was defined as a waist circumference ≥ 90 cm for men and ≥ 80 for women. Main socioeconomic predictors include socio-residential status based on hukou (household registration) and residence of living (urban hukou living in urban areas—urban residents, rural hukou living in urban areas—migrants, and rural hukou living in rural areas—rural residents); labour market status (agricultural work, non-agricultural work, retirement and other), quintiles of household wealth/assets (long-term household socioeconomic status) and household per capita consumption (short-term household socioeconomic status). Logistic regression was performed for women and men separately. Adjusted odds ratios with 95% confidence intervals following logistic regression to account for confounding variables were presented. Results The results show substantial socioeconomic disparities in CVD risks among middle-aged and older people in China. For men, migrants (OR: 0.79, 95% CI: 0.64, 0.98) and rural residents (OR: 0.60, 95% CI: 0.49, 0.72) are less likely to be overweight (and obesity) compared to urban residents. The OR for rural men developing abdominal obesity is 0.59 (95% CI: 0.47, 0.73). Labour market status is closely associated with the odds of developing overweight (and obese) and abdominal obesity for men and women. Compared to people who work in agricultural sector, those who work in non-agricultural sectors (OR: 1.64, 95% CI: 1.39, 1.92 for men; OR: 1.51, 95% CI: 1.25, 1.83 for women) and those who already retired (OR: 1.75, 95% CI: 1.46, 2.09 for men; OR: 1.81, 95% CI: 1.55, 2.10 for women) are more likely to be overweight. For abdominal obesity, the ORs are 1.63 (95% CI: 1.36, 1.97) for men with non-agricultural work and 1.66 (95% CI: 1.35, 2.05) for retired men. The corresponding ORs for women are 1.15 (95% CI: 0.91, 1.45) and 1.68 (95% CI: 1.39, 2.03), respectively. Being married/partnered appears to significantly increase the odds of being overweight (and obese) and decrease the odds of hypertension for both men and women. Short-term household economic status shows a modest and graded association with the odds of all CVD risk including overweight (and obesity), abdominal obesity and hypertension at higher quintiles compared to bottom quintile. Conclusions There are substantial socioeconomic inequalities in CVD risks among Chinese middle-aged and older people, which can be further enhanced by China's rapid urbanisation and ageing. Since China's urbanisation is strongly driven by state. There is, therefore, a possibility that socioeconomic inequalities among older people might be ‘broken’ provided appropriate policy interventions are put in place. The findings will aid an understanding of identifying modifiable risk factors that can prevent avoidable health inequalities, and developing evidence-based policies to tackle health inequalities among older people in China.