| Background Recently,overweight and obesity has become a major threat to the health worldwide.The association between body mass index(BMI)and type 2 diabetes mellitus(T2DM)has been studied in previous studies.However,the association between BMI,BMI change and risk of T2 DM in different periods of adulthood has not been clarified clearly in Chinese population,especially in female and male separately.In China,the incidences of obesity,T2 DM and breast cancer are increasing rapidly,with complicated inter-relationships among these diseases.Thus,we aimed to investigate the association among BMI change in different periods of adulthood with risk of T2 DM and female breast cancer in Chinese population.Methods The REACTION study(Risk Evaluation of Cancers in Chinese Diabetic Individuals: a Longitudinal study,REACTION)is an ongoing multicenter prospective observational study.In 2011-2012,259657 participants from 25 communities,aged 40 years or older,were included in the study at baseline.1.The association between obesity,BMI change and risk of T2 DM.Standard questionnaires were used to collect information on lifestyle,medical history and use of medications.We performed anthropometric measurements,including body height,weight and blood pressure taken in seated position.All participants underwent an OGTT(oral glucose tolerance test,OGTT)test.Blood samples were taken for biochemical analysis which included plasma glucose,lipid,insulin levels and liver and kidney function.Follow-up visit was taken place in 9 communities in 2014 to 2015,with 69.3% of the baseline participants completed the follow-up(61091 of 88047 participants).The study of association between the BMI change from early adulthood to midlife and subsequent T2 DM finally included 120666 middle-aged and elderly,whose retrospectively self-reported body weight at 20,40 years and measured height were available.While,the prospective study of association between the BMI change from baseline to follow-up and subsequent T2 DM finally included 42602 participants.2.The study of association between the BMI change from early adulthood to midlife and subsequent breast cancer risk finally included 84586 female at baseline.3.In the cross-sectional study of association between the status of glucose metabolism as well as glucose indicators and breast cancer risk,164572 female were included at baseline.While,in the prospective study,37805 female entered the final analysis.All analyses were performed using SAS version 9.3(SAS Institute,Cary,NC).Results 1.The association between obesity,BMI change and risk of T2 DM.(1)Compared to participants with normal weight in the early adulthood,the overweight or obese participants had higher risk of T2 DM after midlife(OR,1.39;95%CI,1.33-1.45),while the risk was reduced in the population with BMI less than 18.5 in the early adulthood(OR,0.94;95%CI,0.90–0.98).Compared with participants of stable weight,the weight-gain population(mild increase and significant increase)from early adulthood to midlife had increased risk of T2 DM,while the weight-loss participants had reduced risk(no relationship between weight-loss and reduced T2 DM risk was observed in male).In the cross-tabulation of both early-adulthood BMI and BMI change,the odds ratio of T2 DM increased across both variables.Subgroup analysis showed greater association between weight gain in early adulthood and risk of T2 DM in male than in female.(2)Compared with participants of normal weight at baseline,the overweight or obese participants had higher risk of T2 DM in the follow up(OR,1.87;95%CI,1.76-2.00),while the risk was not different in the population with BMI less than 18.5 at baseline(OR,0.96;95%CI,0.76-1.23).Compared with participants of stable weight,the weight-gain population(mild increase and significant increase)in the follow up had increased risk of T2 DM,while the weight-loss participants had reduced risk.In the cross-tabulation of both baseline BMI and BMI change,the odds ratio of T2 DM increased across both variables.Subgroup analysis showed greater association between weight gain after midlife and risk of T2 DM in female than in male.2.The study of association between the BMI change from early adulthood to midlife and subsequent breast cancer risk.BMI in early adulthood was not associated with breast cancer risk after midlife.In postmenopausal rather than premenopausal female,significant weight gain from early adulthood to midlife increased subsequent breast cancer risk compared to weight loss(OR,1.36;95%CI,1.01-1.83).3.The association between glucose metabolism and breast cancer risk.(1)In the postmenopausal female of the cross-sectional study,compared to non-diabetic population,diabetes patients had 46% higher(OR,1.46;95%CI,1.10-1.95)risk of breast cancer.In non-diabetic female,hyperinsulinemia and postchallenge plasma glucose(PPG)better indicated the risk of postmenopausal breast cancer.While in diabetic women,the association between hyperinsulinemia and breast cancer was observed in premenopausal women.(2)In the follow up study,we observed the association between hyperinsulinemia and postmenopausal breast cancer in non-diabetic female.Conclusions The findings from Chinese population indicated that weight control in different periods of adulthood were closely related to risk of T2 DM and postmenopausal breast cancer.The initial BMI and BMI change in different periods of adulthood have indicated accumulative effect on risk of T2 DM in later life.Individuals with higher initial BMI had higher risk of T2 DM with weight gain.Meanwhile,the higher weight gain,the greater the risk of T2 DM.The association of weight gain and T2 DM was more evident in male than female in early adulthood,while,this relationship became more evident in female than male after midlife.Weight loss could significantly reduce the risk of T2 DM.In postmenopausal female,significant weight gain from early adulthood to midlife and T2 DM both increased breast cancer risk.The results suggested that the strict control of body weight and weight stability after midlife,could help prevent diabetes and the occurrence of female breast cancer.Also,blood glucose management and improving hyperinsulinemia could help prevent occurrence of female breast cancer. |
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