The present study included 888,143 individuals aged 18 to 96 undergoing health examination in the West China Hospital, Sichuan University during 2009 to 2017. This large sample data showed high blood lipids distribution and high percentage of lipids levels in both males and females in the local population. All samples were measured in the West China Hospital, Sichuan University to support the accuracy and stability of the results.
This study showed that the levels of blood lipids were increased year by year in both males as well as females, and similarly the percentage of high lipids levels was also increased from 2009 to 2017. Compared to women, men had lower levels of HDL-C and significantly higher levels of total cholesterol, LDL-C, triglycerides. This finding was similar to that of the previous study, in which a high incidence of dyslipidemia was observed in males than in females[4–6]. Men may be a risk factor for dyslipidemia. This phenomenon may be caused by excessive accumulation of fat, which is caused by considerable stress and lack of adequate exercise, since men are the main labor force in society. In addition, men smoke and drink more and to a greater degree than women, both of which are linked to dyslipidemia. Moreover, estrogen leads to a reduction in LDL cholesterol and triglycerides, providing relative protection against coronary heart disease in young women.
We found that the ages group(51–60) had the highest level appeared in the three lipids(cholesterol, triglyceride and LDL-C) level, which was the opposite phenomenon of the HDL-C level. People aged < 60 would take more high-calorie, high-fat, high-sugar diets than the older individuals. Moreover, the intensity and frequency of exercise among people between the ages of 51 and 60 are lower than that of younger people. Thirdly, study from Ndahimana et al Suggested that older individuals have lower resting energy expenditure compared to younger people. The above three factors make people aged 51–60 eat more fat and consume less fat, which leads to the occurrence of dyslipidemia.
With rapid economic growth and associated industrialization, urbanization, and lifestyle changes (high-calorie, high-fat, high-sugar diets and decreased physical activity), CVD has reached epidemic proportions in Chinese population. In our study, the percentage of population with high levels of blood lipids was increased in both males and females year by year up to 2015. It is estimated that the number of cardiovascular and cerebrovascular diseases in China is 290 million, including 13 million patients with stroke and 11 million patients with coronary atherosclerotic heart disease (CHD). In the past 20 years, the age-standardized prevalence rate of cardiovascular and cerebrovascular diseases has increased by 14.7%. According to World Bank estimates, the number of stroke and coronary heart disease will increase to 31.77 million and 22.63 million respectively by 2030. Zhang et al found that the prevalence of dyslipidemia in the young population in Wenzhou is relatively high. Young people should increase their health promoting behaviors and consider the factors influencing dyslipidemia to lower the prevalence of dyslipidemia. Therefore, regular physical examination is an important method for early detection of abnormal blood glucose levels, which assists in taking active medical measures for correcting the blood lipids levels.
As the data was obtained through laboratory information system system, this study adopted screening intervention research method in the epidemiological survey to analyze the variations in the trends of blood lipids concentrations in different genders, different age groups and different years. One of the most important reasons for using big data is due to its accuracy of clinical trial results. To ensure the quality of the data that we collected, sample processing was conducted in accordance with the standard operating procedures of the laboratory. To ensure the reliability of the measurement results, the internal quality control data was verified during the study process.
There are major and distinctive strengths in our study including the large sample size and highly standardized sampling method. However, some limitations should be noted. Firstly, our study was a population-based cross-sectional study with no strict follow-up design. The prevalence of dyslipidemia was based on questionnaires and measurements during a single visit, implying that our results could have been affected by recall bias and unmeasured confounding. Secondly, the definition of dyslipidemia in our study is based on the Chinese guidelines for the prevention and treatment of dyslipidemia in adults, and we should compare our results with those obtained in other countries. Further epidemiological studies are needed to obtain more comprehensive information for the development of prevention and control measures. Thirdly, the information regarding diet and exercise of health examination population were missed. The relationship between blood lipids levels and the above related factors was not explored.
In conclusion, dyslipidemia happens more in males than females. The rate of dyslipidemia increased with age but it appears most obvious in aged 51–60. It is necessary to take steps to control lipids levels in adults, especially in males and the aged population of 51–60. The public should pay more attention on early education and intervention to prevent the development of dyslipidemia.