Analysis of the Detection and Inuencing Factors of Dyslipidemia in the Elderly in Wuwei (cid:0) A Community-based Study

Background: This study aimed to investigate the distribution of the incidence of dyslipidemia among the elderly in Wuwei, and explore the related factors affecting dyslipidemia. Methods: The physical examination data of 43,092 elder people aged 60 and over from 2012 to 2019 in Wuwei city were collected to analyze the incidence of dyslipidemia, and the factors affecting dyslipidemia were evaluated by univariate and multivariate analysis. Results: A total of 12,338 cases of dyslipidemia were reported in 43,092 patients, and the incidence of dyslipidemia was 28.6%. Among these dyslipidemia patients, the proportion of patients with low high-density lipoprotein cholesterol was the highest, and the proportion of patients with hypertriglyceridemia combined with low high-density lipoprotein cholesterol was the lowest. Univariate analysis showed that age, gender, smoking, alcohol consumption, blood glucose, blood pressure, weight, electrocardiogram, and total bilirubin were the inuencing factors of dyslipidemia in the elderly, and the differences were statistically signicant (P < 0.05). Multivariate logistic regression analysis indicated that female gender, overweight/obesity, abnormal blood glucose, and high alanine aminotransferase were independent risk factors for dyslipidemia in the elderly (P < 0.05). Conclusions: The age with the highest prevalence of dyslipidemia among the elderly in Wuwei city is 70–80 years old. Elderly women should strengthen the prevention and treatment of dyslipidemia. In order to avoid the occurrence of dyslipidemia, it is necessary to control body weight, blood glucose and improve liver function.


Background
Blood lipids are a general term for cholesterol, triacylglycerol (TG) and lipids (such as phospholipids) in serum, and the clinically relevant blood lipids are mainly cholesterol and TG. Dyslipidemia refers to abnormal metabolism of lipoproteins in the human body, mainly including elevated total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triacylglycerol (TG) levels, or decreased high-density lipoprotein cholesterol (HDL-C) levels [1] . Some research reports have pointed out that the prevalence of dyslipidemia in people elder than 35 years in China was 34.7% from 2012 to 2015 [2] , the blood lipid level in the Chinese population gradually increased, and the detection rate of dyslipidemia signi cantly increased [3] . Dyslipidemia is one of the important mechanisms leading to atherosclerosis, which in turn leads to the occurrence of cardiovascular and cerebrovascular diseases [4] . The incidence of cardiovascular diseases is high among the elderly, and the incidence increases with the aggravation of the aging phenomenon in China. Therefore, the prevention and treatment of dyslipidemia in the elderly have become a clinical concern. At present, there are few surveys or studies on dyslipidemia in the elderly in northwest China. Based on the above reasons, this study retrospectively analyzed the physical examination data of the elderly in Wuwei City, investigated the epidemic status of dyslipidemia in Wuwei City and analyzed its possible risk factors to provide a reference for the current status and prevention of dyslipidemia.

Study object
A retrospective analysis of the elderly population underwent routine physical examinations from 2012 to 2019 in Dongguan Street Community Medical Examination Center, Liangzhou District, Wuwei City. A total of 43092 subjects with complete physical examination data were included in this analysis, including 24553 males (57%) and 18539 females (43%), aged 64-104 years, with a mean age of (72.37 + 5.46) years. In this analysis, only the age, gender and physical examination conclusion of the study subjects are extracted for data analysis, and no personal identity information and medical ethics issues of the traceable study subjects are involved. Therefore, informed consent and ethical review of the study subjects are not required.

Methods
In this study, the data of the physical examination report were analyzed based on the criteria or guidelines for biochemical indicators for related diseases of dyslipidemia, and the abnormal electrocardiograph (ECG) results in the physical examination report were directly used for analysis. The conclusion of the subjects' disease and the judgment results of the indicators were summarized as binary variables (i.e., normal/abnormal or normal/high). Besides, the drinking and smoking status of subjects were recorded and analyzed.

Diagnostic criteria
According to the "2016 Chinese guideline for the management of dyslipidemia in adults", dyslipidemia was de ned as TC ≥ 5.2 mmol/L, TG ≥ 1.7 mmol/L, LDL-C ≥ 3.4 mmol/L, and HDL-C < 1.0 mmol/L. Abnormalities in any one or more of the above indicators can be judged as dyslipidemia. Dyslipidemias can be generally divided into hypercholesterolemia, hypertriglycerdemia, mixed hyperlipidemia, and Low HDL-C.
Criteria for overweight and obesity have given in "The Guidelines for Prevention and Control of Overweight and Obesity in Chinese Adults": Body mass index (BMI) is calculated as weight in kilograms divided by the square of height in meters. BMI < 18.5 is considered underweight, 18.5kg/m 2 ≤ BMI < 24.0kg/m 2 is considered normal, 24.0kg/m 2 ≤ BMI < 28.0kg/m 2 is considered overweight, and BMI ≥ 28.0kg/m 2 is obesity.

Statistical methodology
The SPSS23.0 statistical software was used to process the data., and the measurement data were expressed as mean ± standard deviation (± s) and analyzed by a t-test. Enumeration data were expressed as a rate (%) and analyzed by the χ 2 test. Multivariate logistic regression was performed to analyse the in uencing factors. The difference was statistically signi cant when P < 0.05.

Distribution of dyslipidemia
Of the 43092 elder people included in this analysis, 12338 were detected with dyslipidemia, and the prevalence of dyslipidemia was 28.6%. Low HDL-C accounted for the majority of dyslipidemia diseases, accounting for 48.28%. The lowest detection rate was high TG combined with low HDL-C (1.81%). Among patients with dyslipidemia, 54.53% were females, and 45.47% were males. The detection rate of low HDL-C in male patients was signi cantly higher than that in female patients, and the difference was statistically signi cant (P < 0.05). There was no statistically signi cant difference in the proportion of high TG combined with low HDL-C and high TC combined with high TG and low HDL-C between genders (P > 0.05). (As shown in Table 1) Table 1 Distribution status of dyslipidemia in males and females (n (%)).

Multivariate Logistic regression analysis
Whether the lipid pro le was abnormal or not was taken as the dependent variable (0 = normal, 1 = abnormal) and the factors in uencing blood lipids in univariate analysis (P < 0.05) were used as independent variables for multivariate Logistic regression analysis.OR > 1, P < 0.05). (Table 3) The results of the analysis con rmed that female gender, overweight/obesity, abnormal blood glucose, and high ALT may all be the risk factors for dyslipidemia in the elderly population.

Discussion
This study found that the prevalence of dyslipidemia was 28.6% in the elderly in Wuwei, of which the incidence was 15.61% in males and 13.02% in females. It showed that the incidence of dyslipidemia in males was signi cantly higher than that in females, and the difference was statistically signi cant. Next, according to the proportion of related dyslipidemia types obtained from the included data, the highest incidence of dyslipidemia is low HDL-C, and the lowest incidence is high TG combined with low HDL-C.
It is the same as the result that the highest incidence of dyslipidemia diseases is low HDL-C among the general population by some researches [6] . However, it is inconsistent with the constituent ratio of dyslipidemia in the elderly in Zhongshan City in the study [7] . The cause of this difference may be related to regional factors or dietary habits, and the speci c reason needs to be further studied.
Multivariate logistic regression analysis demonstrated that age, gender, overweight/obesity, hyperglycemia, and high AST are independent risk factors for dyslipidemia in elderly patients. Also, the epidemiological research report of dyslipidemia pointed out that there are differences in the incidence of different ages and different genders, and this is consistent with the conclusions drawn from our study. The results of the analysis also found that elderly women had a 1.14-fold higher risk of dyslipidemia than men. The loss of estrogen's protective effect on lipid metabolism or associated changes in endocrine metabolism after menopause in elder women may be responsible for this result [8,9] . Therefore, the prevention and treatment of dyslipidemia in elder women should be strengthened in clinical practice.
The results of this study indicated that the risk of dyslipidemia is higher at the age of 70-80 years than that at the age of 60-70 years, and the risk of disease is reduced after the age of 80. But in previous existing studies, the reported age levels of the high incidence of dyslipidemia vary, and the mechanism of changes in blood lipid levels with age has not been clari ed [10] .
Overweight/obesity is also a risk factor for dyslipidemia, while underweight patients have a low risk of dyslipidemia, and it indicates that dyslipidemia is associated with obesity. Insulin resistance in obese subjects reduces LDL-C level and reduces lipoprotein lipase activity, both of which cause slow clearance of very-low-density lipoprotein, TC, LDL-C, etc., thereby triggering abnormal lipid changes [11] .
Previous studies have found that elder people with abnormal liver function have an increased risk of dyslipidemia, and the two are mutually causal [12] . Our study demonstrated that ALT, a diagnostic indicator of liver function, is a risk factor for dyslipidemia, which is the same as the conclusion of the previous conclusion. The liver is the main organ for the breakdown and synthesis of blood lipids; After it injury, the rate of blood lipid degradation is slowed down and the lipid part in the blood cannot be cleaned in time. Excessive deposition occurs in the hepatocytes. In ammatory necrosis and cellular brosis are induced after the activation of related cells [13] . Therefore, attention should be paid to the treatment of liver dysfunction in the elderly group with liver dysfunction to reduce the occurrence of dyslipidemia.
Previous studies have indicated that smoking and alcohol consumption are independent risk factors for dyslipidemia [14][15][16] . However, this study did not nd an effect of smoking and alcohol consumption on dyslipidemia. The possible reason for the different conclusions may be that this physical examination data recorded the frequency of alcohol consumption and smoking but did not clearly record the amount of smoking and alcohol consumed.

Conclusions
In summary, the incidence of dyslipidemia was relatively low among the elderly population in Wuwei, and female gender, overweight/obesity, abnormal blood glucose, and high ALT are risk factors for dyslipidemia. Therefore, it is recommended that the elderly population in this area improve life habits, control body weight, improve liver function. In particular, strengthen the prevention and treatment of dyslipidemia in the elder women, so as to reduce the risk of dyslipidemia and reduce the occurrence of cardiovascular disease.