Analysis Of The Associations Between Obesity Indices And Left Ventricular Mass In Rural Population

PART Ⅰ ANALYSIS OF THE ASSOCIATIONS BETWEEN OBESITY INDICES AND LEFT VENTRICULAR MASS INDEXObjective: Hypertension is a major risk factor for myocardial remodeling.The morbidity of hypertensive populations was 31.1%worldwide in 2010 and it continues to increase.The left ventricular mass index(LVMI)is utilized to evaluate the target organ damage in patients with hypertension,and it is also a key indicator of risk stratification in hypertensive patients.Obesity is a chronic metabolic disease caused by a variety of factors.Obesity,especially abdominal obesity is not only one of important component of the metabolic syndrome(MS),but is also closely related to hypertension and a series of metabolic abnormalities.The World Health Organization has reported that there are more than 1.9 billion overweight people,600 million of whom were obese in 2014.Observational studies have identified associations between adiposity and the risk of developing incident coronary heart disease,stroke,type 2diabetes mellitus(T2D),hypertension,and left ventricular hypertrophy(LVH).In addition,more studies have suggested that central adiposity,measured as either the waist-hip ratio(WHR)or the waist circumference(WC),may have stronger associations with cardiovascular disease(CVD).Epidemiology had fully confirmed the correlation between obesity and hypertension,but many obese patients blood pressure is normal,adipose tissue distribution differences may explain the heterogeneity between clinical and biological.However,it is still unclear which obesity index is more associated with LVH.Therefore,we conducted this study to assess the relationship between different obesity indices and LVMI,to provide potential evidence of intervention strategies for obesity and related CVD.Methods: In this study,501 men and 534 women aged 21-89 years,residing in the Tongnan District of Chongqing,which is a rural area of Western China,were selected for participation by multistage stratified random sampling.Information of demographic characteristics,including smoking status,alcohol status,salt intake,and education level were collected via a questionnaire.Height,weight,waist circumference(WC),resting pulse,ankle arm index,blood pressure,percentage body fat(PBF),visceral adiposity index(VAI),LVMI were measured.Triglycerides,total cholesterol,low-density lipoprotein cholesterol,high-density lipoprotein cholesterol,creatinine,serum potassium,urine microalbumin,and fasting blood glucose levels were measured using standard enzymatic methods.First,the population was divided into the MS group and the non-MS group,and the differences of baseline data and LVMI between the two groups were compared.Then WC,Body mass index(BMI),PBF,VAI were compared between LVH group and non-LVH group and regression analysis of various obesity indicators and LVH was conducted.Finally,the association between VAI and LVH was explored using multiple regression analysis in all subjects(n = 1,035).Results:1.In rural areas of Chong Qing,there were 198 residents with MS,accounting for 19.13% of all subjects,including 54 males(27.3%)and 144females(72.7%),with a higher proportion of females(P=0.000).There was no significant difference in LVMI between the MS group and the non-MS group(102.45 19.75 g/m2 vs.100.90 23.78 g/m2,P=0.341),although the average value of LVMI in the MS group was slightly higher.2.Among the enrolled patients,885(85.51%)patients were in the non-LVH group,and 150(14.49%)patients were in the LVH group.There were no statistically differences in BMI,WC and PBF between the two groups(P > 0.05),and there was significant statistically difference in VAI between the two groups(P=0.000).3.The increase of BMI was correlated with LVH(OR=1.072;1.011,1.137,P=0.020),and the BMI was still associated with LVH when added WC(OR=1.108;1.012,1.213,P=0.026)or PBF(OR=1.121;1.049,1.199,P=0.001)to the model.However,when VAI was added to the model,the increase of VAI was the only obesity parameter related to LVH(OR=1.151;1.046,1.267,P=0.004),and BMI was no longer associated with LVH(P=0.123).4.The VAI was the only obesity index that associated with LVH(OR= 1.107;95% CI 1.065,1.150,P=0.000).After adjusting for age,gender,smoking,drinking,education level,salt intake,blood lipid,blood glucose,creatinine,blood pressure and BMI,VAI was still correlated with LVH(OR= 1.134;95%CI 1.025,1.254,P=0.015).Conclusions: Visceral fat index is an independent risk factor for left ventricular hypertrophy.Reducing the VAI rather than the BMI or WC may prevent LVH complications in obese hypertensive patients.PART Ⅱ ANALYSIS OF THE ASSOCIATIONS BETWEEN OBESITY INDICES AND LEFT VENTRICULAR MASS INDEX IN DIFFERENT AGE SUBGROUPSObjective: China’s elderly population over 60 years old had reached212 million,accounting for 15.5% of the total population in 2014 and our country had entered the aging society.With the improvement of medicine and the change of lifestyle,the incidence of obesity of elderly had increased.In 2013,the proportion of overweight and obesity of ≥60 years old population in our country were 32.10% and 12.10% respectively,and recently China’s rural elderly overweight and obesity rates increased faster than that of city,its prevalence was also close to the city.However,the age,education level,lifestyle and medical history of the elderly population were different from the general population,it was of certain significance to explore the characteristics of obesity in the elderly population.Although obesity was currently a hot topic in clinical research,data of the characteristics of obesity in the elderly are limited.Studies had shown that obesity in young and middle-aged people significantly increases the risk of hypertension,type 2 diabetes and CVD,but in the elderly,the correlation between obesity and CVD was still controversial.Which indicators was more appropriate to evaluate the obesity of the elderly,and whether the elderly need to lose weight need further research.In the first part of thestudy,we found that VAI was an independent risk factor for LVH,and reducing VAI instead of BMI or WC could reduce LVH in patients with obesity and hypertension,but age was not stratified.The second part of this study analyzed the difference of obesity between the elderly population and the middle-aged and young population,and explored the relationship between the obesity evaluation index and the risk of LVH in the elderly population,so as to provide references for the weight management and the intervention of LVH in the elderly.Methods: In the first part of this study,1035 rural residents were finally included.According to the international classification standard for the elderly,they were divided into < 65 years old subgroup(713)and ≥ 65 years old subgroup(322).Salt intake,BMI,WC,PBF,VAI,SBP,DBP,HR,ABI,TC,TG,LDL,HDL,FBG,MAU,Cr and LVMI were compared between the two subgroups.Then,the association between obesity index and LVH was explored using multiple regression analysis in different age subgroups.Results:1.Compared with the < 65 years old subgroup,residents in the ≥ 65 years old subgroup had lower BMI,WC and higher SBP,HR,FBG,MAU,VAI and LVMI(P < 0.05).There were no differences in salt intake,PBF,DBP,ABI,Cr,TC,TG,LDL,HDL levels between the two subgroups(P >0.05).2.In the subgroup of patients aged <65 years,both SBP(OR = 1.047,95%CI 1.025,1.070,P<0.001)and VAI(OR = 1.272,95%CI 1.092,1.481,P=0.002)were risk factors for LVH.3.In the subgroup of patients aged ≥65 years,only SBP(OR = 1.019,95%CI 1.002,1.037,P=0.032)was a risk factor for LVH,and there was no association between VAI and LVH anymore(P=0.35).Conclusions: BMI and WC were not suitable for the assessment of elderly obese patients,and VAI may be an appropriate indicator.In order to prevent LVH,the strict control of blood pressure and VAI were both important for patients younger than 65 years old,but for patients older than65 years old,the control of blood pressure should be given priority.PART Ⅲ ANALYSIS OF THE ASSOCIATIONS BETWEEN OBESITY INDICES AND LEFT VENTRICULAR MASS INDEX IN PERIMENOPAUSE SUBGROUPSObjective: Epidemiological investigations had shown that the obesity rate of females was rising much faster than that of males.In 2006,the average waist circumference of adult males aged 20-65 years in China was82.9cm,and the rate of central obesity was 42.5%,and in females the mean waist circumference was 78.9cm,and the rate of central obesity was 46.9%.The female had rapid changes of endocrine hormone level stage in menopausal transition.Compared with men,metabolic disorders occur less than premenopausal women,but in menopausal transition,women estrogen levels decreased,testosterone levels and oxidative stress increased,metabolic disease such as hypertension,MS,type 2 diabetes,coronary heart disease increased significantly,obesity in middle-aged and old women are more popular than that of men.At present,there were many researches on postmenopausal metabolic changes and diseases,but few on perimenopause.The increase of obesity rate in perimenopausal women was the main causes of obesity in postmenopausal women,and it was difficult for elderly women to lose weight due to various reasons.Therefore,in order to prevent and control the disease burden of elderly women caused by obesity,it is necessary to start from perimenopause.In the third part of thisstudy,the characteristics of obesity in perimenopausal women were studied to discuss the importance of perimenopausal and which indexes were most suitable for assessing the relationship between obesity and left ventricular hypertrophy,so as to provide epidemiological basis for weight management and intervention of left ventricular hypertrophy in perimenopausal women and even later elderly women.Methods: In the first part of this study,1035 rural residents were finally included.According to the definition of perimenopausal period,women aged 40-65 were included in the subgroup of perimenopausal women(n=319),and those ≥ 65 years old were included in the subgroup of elderly women(n=148).BMI,WC,PBF,VAI,SBP,DBP,HR,basal metabolic rate,ABI,TC,TG,LDL,HDL,FBG,MAU,Cr and LVMI were compared between the two subgroups.Then,the association between obesity index and LVH was explored using multiple regression analysis in perimenopausal women.Finally,the perimenopausal period,visceral fat index and blood pressure were included in the logistic regression equation to analyze the effect of perimenopausal on left ventricular hypertrophy.Results:1.Compared with the elderly women subgroup,the perimenopausal women subgroup had lower PBF,SBP,HR,MAU,Cr,LDL,FBG,LVMI and higher BMI,WC,basal metabolic rate and ABI(P < 0.05).There were no significant differences in VAI,DBP,serum potassium,TC,TG,andHDL levels between the two groups(P > 0.05).2.In the subgroup of perimenopausal women,both SBP(OR = 1.059,95%CI 1.022,1.096,P=0.001)and VAI(OR = 1.432,95%CI 1.095,1.872,P=0.009)were risk factors for LVH,and there was no association between PBF and LVH(P=0.082).3.Perimenopausal period,blood pressure and visceral fat index were included in the multivariate regression equation.It was found that after adjusting for blood pressure and visceral fat index,the relative risk of perimenopausal population was 1.786(95%CI 1.125,2.837,P=0.014).Conclusions: Visceral fat index is the only obesity index related to left ventricular hypertrophy in perimenopausal women.Perimenopause is an independent risk factor for left ventricular hypertrophy.For female with hypertension,prevention and control of obesity and left ventricular hypertrophy should start from the perimenopause.