The epidemiology of dyslipidaemia in the cardiovascular epidemic in China

Abstract

Background In recent decades, the prevalence of cardiovascular diseases (CVDs) around the world has been increasing, and researchers have paid more attention to understand the epidemiology of CVDs to provide reference for healthcare professionals and policy makers. China is one of the countries where rapid development of economy occurs accompanied by changes in people’s socioeconomic status and lifestyle, and is also facing the challenge of increasing burden of CVDs. This challenge exists not only in the rising prevalence of CVDs and increasing deaths from CVDs, but also in the low awareness and treatment rates of some CVDs. This Master research will focus on one important risk condition of CVDs, abnormal blood lipid levels or called dyslipidaemia, as a window to help understand more about the cardiovascular epidemics in China in recent years, based on secondary data analysis of a representative cohort study called China Health and Retirement Longitudinal Study. (CHARLS).

Objectives This Master research aims to provide a reliable estimation of the prevalence, awareness, treatment and control rates of dyslipidaemia in middle-aged and elderly population in China, and analyse their related influential factors.

Methods This research includes two phases of analysis: Phase 1: A cross-sectional study of the CHARLS baseline survey to investigate the prevalence, awareness, treatment and control rates of dyslipidaemia, using the blood test data from CHARLS.

Phase 2: A cohort study of the CHARLS baseline and follow-up surveys to estimate the changes in prevalence, awareness and treatment rates of dyslipidaemia and to investigate related influential factors for the development, awareness and treatment uptake of dyslipidaemia.

Results In the cross-sectional study of the baseline data, the weighted prevalence, awareness, treatment and control rates of dyslipidaemia were 43.8% (95%CI: 42.8, 44.8%), 22.7% (95%CI: 20.9, 24.6%), 13.5% (95%CI: 11.7, 15.2%) and 5.1% (95%CI: 4.3, 5.8%), respectively. Urban residents had significantly higher prevalence, awareness and treatment rates of dyslipidaemia compared with rural residents, while the control rates did not differ significantly.

In the cohort study of the baseline and two follow-up surveys, the estimated prevalence of dyslipidaemia did not increase much from 2011 to 2015, while the awareness and control rates in both urban and rural areas increased significantly. Waist circumference (cm, OR: 1.04, 95%CI: 1.02, 1.07) was identified as the most important predictors for the development of dyslipidaemia during the observation. Urban residence (OR: 1.50, 95%CI: 1.10, 2.05) and higher education (OR: 1.69/1.97/1.64 for primary/secondary/high school or higher compared with illiterate education level) were found to be significantly associated with awareness of dyslipidaemia, while awareness of dyslipidaemia (OR: 5.75, 95%CI: 3.95, 8.36) was directly associated with the treatment uptake of dyslipidaemia.

Conclusions Dyslipidaemia was found to be widespread in China with high prevalence, but its awareness, treatment and control rates remained relatively low, indicating its poor detection and inadequate control. However, the awareness and treatment rates were gradually increasing over years, possibly showing the outcomes of China’s healthcare reform and public health promotion programs.

Obesity was a crucial contributor of dyslipidemia, and therefore management of dyslipidemia could refer to obesity management for policy making. Urban residence and higher education were important for awareness of dyslipidemia, while awareness was important for treatment uptake, so public education programs of health promotion were needed to raise awareness of dyslipidemia and better manage dyslipidemia epidemic in China.