Study On The Relationship Between BMI And Serum TSH Level In Rural Residents Of Fujian Coastal Area

[objective]To detect the current status of the rural population in coastal areas of overweight/obesity,to explore the association between BMI,Waist,blood lipid and TSH.In patients with subclinical hypothyroidism,analyzed the level of anti-thyroid antibody in overweight/obese population.[Method]We analyzed data from a rural population epidemiological survey conducted in 2016 in Rural Residents of Fujian Coastal Area,In all,1136 participants were investigated,the epidemiological survey form collected through questionnaire-s,measureent of the height,weight,waist circumference,thyroid peroxidase antibody（TPOAb）,serum thyroid stimulating hormone（TSH）,if TSH is abnormal,it will add the measurement of free thyroxine（FT4）and three free triiodothyronine（FT3）.Body mass index（Body mass,index,BMI）=weight（kg）/height（M²）.The diagnosis of thyroid disease by standard endocrine branch of Chinese Medical Association 2007 for the management of thyroid disease in China.All subjects with younger than 18 years old,the local living under 5 years,pregnant women and women with a pregnancy within 12 months,with previous or present thyroid dysfunction,recently taking drugs that affecting thyroid function,subclinical hyperthyroidism is 3 cases,the small number of cases will not be discussed,BMI under18.5kg/m^2,.incomplete information were excluded,976 cases were eligible for these analyses.The normal level of TSH is 0.27-4.2mIU/L,according to the thyroid disease diagnosis and treatment guidelines proposed 1.0-1.9mIU/L is the safe range of TSH,TSH will be divided into 4 groups,A（0.27<TSH<1.0mIU/L）,B（1.0≦TSH≦1.90mIU/L）,C（1.91≦TSH≦4.2mIU/L）,D（TSH>4.2mIU/L）;Statistical analysis was performed using SPSS 22 software.Results was expressed as mean±s.d for variables with normal distribution.Analyses were performed in linear models（ANOVA）and logistic regression analyses to consider confounding from other factors with a possible association with BMI.The comparison of independent samples were analyzed using single factor analysis of variance,Categorical variables usingχ²test,Correlation betwee-n two variables was ascertained by Spearman’s correlation tests,Analyses were perfor-med in logistic regression analyses to consider confounding,the correlation between BMI,waist circumference and TSH;The level of significance was set to5%,were two-sided test.[Results]1.The total prevalence of overweight/obesity was 480 cases（42%）;male abdominal obesity was 227 cases（20%）,268 cases were female（23.6%）.In the final group,there were 976 cases,including 471 males（48.3%）and 505 females（51.7%）.There were 78 patients with subclinical hypothyroidism（n=8%）.2.The possible confounding factors that effect BMI and waist:age,education level,gender,occupation,income are the confounding factors of BMI and waist,there were no significant differences in BMI between the two groups of smoking and non-smok-ing,and the two groups were statistically significant differences in waist circumference.3.The correlation between BMI,waist circumference and serum TSH levels after exclusion of confounding factors:BMI,and waist circumference were significantly associated with serum TSH（p<0.05）,in which men,housework,and nonsmokers were risk factors for elevated TSH levels.4.The correlation between TSH and serum lipid levels:TSH and p0.001（r=0.104）,the difference was statistically significant,TSH was not associated with total choleste-rol,low density lipoprotein and high density lipoprotein.In subclinical hypothyroidism group,TSH was positively correlated with triglyceride and low-density lipoprotein,the difference was statistically significant.5.In the subclinical hypothyroidism group,the positive rate of thyroid autoantibodies among different BMI groups:include 7 cases in normal weight group with the anti-thyr-oid antibody positive,13 cases of overweight/obese group with antibody positive,usingχ²test,χ²=0.391,p=0.532,the difference was not statistically significant.[Conclusion]With the increase of TSH,BMI was gradually increased.There was a positive association between BMI and category of serum TSH,TSH was one of the risk factors of obesity and central obesity,and obesity should be considered in the diagnosis of subclinical hypothyroidism.