| Background and ObjectivesYi people,resided in Liangshan Yi Autonomous Prefecture located in Sichuan Province Southwestern China,were used to be renowned for its extremely low hypertension prevalence and unchanged mean blood pressure along with age among Yi farmers.During the past several decades,we have witnessed an enormously increasing trend of hypertension prevalence in China.Furthermore,China is currently undergoing rapidly aging process and tremendous rural-urban migration.However,as the most undeveloped minority in China,little is known about the health status and hypertension prevalence trend of Yi people.Therefore,the objectives of this study are below:1.To systematically explore the trend of hypertension prevalence in Yi people and its associated risk factors.2.To quantitatively estimate the changing relationship between hypertension and some modifiable risk factors,such as body mass index,skeletal muscle mass index,and sarcopenic overweight/obesity.3.To compare the differences between Yi farmers and Yi migrants in health status and demographic characteristic,then provide useful and practical evidence for improving the strategy of preventing cardiometabolic risk factors.Materials and Methods1.This study based on three successive cross-sectional Yi migrant studies in Liangshan Yi Autonomous Prefecture.We used data from 1996,2007 and 2015 periods to investigate the hypertension prevalence in Yi farmers and Yi migrants during the last two decades.Direct standardization was performed using China population age structure from the Sixth National Population Census in 2010 to calculate the standardized hypertension prevalence for each groups.And a geometric progression method was used to predict prevalence of hypertension in the future.To explore related factors of hypertension in each period,we used multivariable logistic regression model to calculate odds ratio(OR)and 95%confidence interval(CI);we also developed a set of nested models to explore potential reasons behind the disparity of hypertension prevalence among periods as well as farmers and migrants.2.According to the results of section 1,we exclusively select BMI as the predicting variable of hypertension risk to quantify the changing relationship between them.At first,calculating the hypertension risk of different BMI groups in each period;then estimate the dose-response relationship between BMI and hypertension.Non-linear relationship between BMI and blood pressure was fitted via multiple linear regression combined with restricted cubic spline.The P-valves of the cross-product interaction term in multivariable logistic model was used to test for the multiplicative interaction.The additive interaction was measured with relative excess risk due to interaction(RERI).According to the definition of population attributable fraction(PAF),the PAF in our study estimated the proportion of hypertension that could be attributed to its association with overweight and obesity.3.Using data from 2015 period,we further investigate possible reasons for the continuous increase of hypertension prevalence both in normal weight group and overweight/obesity group in Yi people.Skeletal muscle mass index is calculated by skeletal muscle mass divided by square of height in meters.Combine SMI and BMI to split Yi people into four groups(Non-overweight/obesity and non-sarcopenia,Non-overweight/obesity sarcopenia,Non-sarcopenia overweight/obesity,Sarcopenic overweight/obesity),we then compare hypertension risk among these groups.Additionally,explore risk factors of sarcopenia and investigate the relationship between SMI and age.Results1.From 1996 to 2015,the standardized hypertension prevalence in Yi people were 7.26%,9.78%,and 16.04%.In Yi farmers,hypertension prevalence were 4.02%,6.28%,and 13.09%.Yi migrants have a higher hypertension risk than Yi farmers,and the prevalence were 10.12%,15.33%,and 19.60%,respectively.The gap of hypertension risk between Yi farmers and migrants is narrowing,and Yi male farmers had the fastest growth rate,from 1996 to 2015,hypertension prevalence in this group increased by 12.25%.The effect of age on hypertension risk is becoming stronger,for each 10 years older,the risk of hypertension increased by 67%(95%CI:1.38-2.02),69%(95%CI:1.52-1.87),and 108%(95%CI:1.92-2.26).The risk disparity of hypertension between periods in male migrants and female farmers could be totally explained by the increase of age and BMI.And the difference of hypertension risk between Yi farmers and migrants was attributed to age,BMI,and education.2.In these three periods,there was a significant increase of hypertension prevalence both in normal weight group and overweigh/obesity group.The prevalence of hypertension increased from 3.69%and 15.14%in 1996 to 11.56%and 26.73%in 2015.The effect of overweight/obesity on hypertension saw an increasing trend in Yi famers,which OR increased from 2.31 to 3.02.For each 2 units increase of BMI,the risk of hypertension in these three periods were increased by 46%(95%CI:1.25-1.71),54%(95%CI:1.43-1.67),and 39%(95%CI:1.31-1.47).Compared with the normal weight in 1996,there is a significant positive additive interaction between period(2007 and 2015)and overweight/obesity.And the attributable proportion of interaction for their join effect is 40.71%and 39%.The PAF increased in the first ten years and leveled off in more recent years,the PAF were 27.66%,33.45%,and 33.26%,respectively.3.Sarcopenia would significantly increase the risk of hypertension in Yi people.When using normal SMI as the reference group,I class sarcopenia increased the risk of hypertension by 41%(95%CI:1.06-1.88),and the number was 167%(95%CI:1.67-4.23)in ? class sarcopenia group.It seems that the detrimental effect of sarcopenia on hypertension is confined with female.Furthermore,among people who older than 45 years,sarcopenia is an independent risk factor of hypertension,? class sarcopenia would lead a 45%(95%CI:1.50-3.98)increase on the risk of hypertension.Among Yi farmers,the hypertension risk for ? class sarcopenia was 3.42(95%CI:1.79-6.43)times higher than normal SMI.Using SMI and BMI to divide the subjects into four groups,for those who has normal BMI,sarcopenia is an independent risk factor of hypertension(OR:1.79;95%CI:1.13-2.79),and the joint effect of sarcooenic overweight/obesity on hypertension risk is 6.76(95%CI:3.96-11.68)times higher than normal group.Conclusions1.Over the past two decades,hypertension prevalence in Yi people has significantly increased.Yi migrants were more likely to be hypertensive than Yi farmers,but the differences were narrowing.Ageing and increasing BMI could largely account for the significant disparity in hypertension prevalence both between different periods and different migration status.2.There was a significant increase of the association between overweight/obesity and hypertension in Yi people.Whereas,the increasing trend has leveled off in more recent years.Overweight/obesity and period(2007 and 2015)had a significant positive additive interaction on the risk of hypertension.Additionally,we observed a continuously growing trend of the hypertension risk among normal weight Yi people.Which remind us that some other body composition measurements may drive this hypertension increase among normal weight people.3.Compared with normal SMI,sarcopenia significantly increase the hypertension risk,but confined with female,older than 45 years,and Yi farmers.For normal weight people,sarcopenia is an independent risk factor of hypertension.And the joint effect of sarcopenic overweight/obesity on hypertension was remarkably larger than the main effect of sarcopenia and overweight/obesity. |
PDF Full Text Request