| BackgroundType 2 diabetes mellitus(T2DM)is one of the common chronic non-communicable diseases and poses a major public health problem worldwide.It is estimated that there are currently more than 537 million T2DM cases in the world.The World Health Organization predicts that the number of T2DM patients worldwide may increase to 640 million by 2040.China reported that 141 million people had suffered from T2DM in 2021.T2DM can cause a variety of diseases,including nerve damage,cardiovascular disease(CVD),kidney failure,amputation,and vision problems.The cost of treating T2DM and its complications is extremely expensive,and thus T2DM poses a huge economic burden on medical care.On the other hand,prediabetes is a state of abnormal blood glucose between normal blood glucose and diabetes.As a pre-diabetic abnormality,prediabetes involves pathological changes of various target tissues related to diabetes.The estimated prevalence of prediabetes was 35.7%in Chinese adults.People with prediabetes have a higher risk of T2DM,and it is estimated that as many as 70%of people with prediabetes will eventually develop T2DM.Nevertheless,prediabetes has not received as much attention as diabetes.Therefore,understanding and controlling diabetes and prediabetes is very important to prevent diabetes and its complications.In recent years,lifestyle changes,including lack of exercise and unhealthy diet,may have played an important role in the prevalence of T2DM.Implementing a healthier lifestyle,increasing physical activity,and reducing body weight based on regulating calorie and fat intake may be the basis for the prevention and treatment of T2DM.However,the extent to which a healthy lifestyle can reduce the risk of T2DM and prediabetes,and the extent to which individual lifestyle factors affect the onset of T2DM and prediabetes is still unclear.The current study explored the association of healthy lifestyle factors with the onset of T2DM and prediabetes and evaluated the association of individual lifestyle factors with the onset of T2DM and prediabetes in a Chinese adult population through a prospective cohort study design.MethodsThe study was conducted based on the Tianjin Chronic Low-grade Systemic Inflammation and Health(TCLSIH)cohort study.The study recruited participants aged18 years and older from the general population living in Tianjin.In total,31,428participants were recruited into the TCLSIH cohort study(participants who had type 1diabetes mellitus(n=129)were not included in the current study).After exclusions,a total of 23,122 participants were available for the lifestyle and T2DM analysis,and18,642 participants for the lifestyle and prediabetes analysis.In the final analyses,all participants completed a structured self-administered health status questionnaire,which was specifically designed for the TCLSIH cohort study.Participants were followed up annually.The endpoint was the occurrence of T2DM(or prediabetes),loss to follow-up,or the last follow-up(December 31,2019).Referring to previous studies,we included five lifestyle factors:body mass index(BMI),smoking,alcohol consumption,physical activity,and diet.According to the standard classification specific for the Chinese population,low-risk BMI was defined as 18.5-23.9 kg/m~2.The low-risk group for alcohol consumption was defined as zero-consumers and those who drank greater than 5 but less than 30 g of alcohol per day for men and 5-20 g for women.For smoking,the low-risk group was defined as currently not smoking.The low-risk group for physical activity was defined as participants who were engaged in a sex-specific upper quarter of the physical activity level.Participants with adherence to the vegetable rich dietary pattern(“Health”dietary pattern)in an upper quarter of the“Health”dietary pattern score were defined as the low-risk diet group.Participants received 1 point(otherwise received 0 point)for each healthy lifestyle factor.Finally,the healthy lifestyle score(range 0-5)was constructed by summing the binary score for each of the five lifestyle factors,with higher scores indicating higher adherence to a healthy lifestyle.The lifestyle score was subsequently categorized into three groups:unfavorable(0 or 1 healthy lifestyle factor),intermediate(2 or 3 healthy lifestyle factors),and favorable(4 or 5 healthy lifestyle factors).T2DM was diagnosed according to the criteria of the China Type 2 Diabetes Prevention Guidelines.Participants were considered to have T2DM if their fasting blood glucose(FBG)≥7.0 mmol/L,and/or 2-hour glucose value during an oral glucose tolerance test(OGTT)≥11.1 mmol/L,and/or glycosylated hemoglobin(Hb A1c)≥48 mmol/mol(6.5%),and/or a history of T2DM.Prediabetes was defined as FBG concentration:5.6mmol/L to 6.9 mmol/L,2-hour plasma glucose concentration:7.8 mmol/L to 11.0mmol/L,or 5.7%to 6.4%Hb A1c levels.Data on potential confounders including age,sex,education level,occupation,family history of CVD,hypertension,and hyperlipidemia were collected with self-administered questionnaires at the baseline survey.Dietary data were assessed by a validated food frequency questionnaire.Height,weight,waist circumference(WC),blood pressure,and biochemical indicators were measured according to standard methods.Baseline characteristics were analyzed according to incident T2DM or prediabetes status and the categories of the lifestyle score.When analyzing the relationship between the healthy lifestyle score and the onset of T2DM and prediabetes,the lowest lifestyle score group(0-1 point)was the reference group,and Cox proportional hazards models were applied to calculate hazard ratios(HRs)and 95%confidence intervals(CIs)for the associations of lifestyle categories and risk of T2DM and prediabetes.The final multivariable models adjusted for age,sex,educational level,occupation,household income,hypertension,hyperlipidemia,family history of disease(including CVD,hypertension,and diabetes),and total energy intake.The multiplicative interaction model was used to analyze the interaction between healthy lifestyle scores and confounding factors on T2DM and prediabetes.In addition,we conducted a sensitivity analysis excluding participants with T2DM and prediabetes that occurred in the first year of follow-up.All analyzes were performed using SAS software version 9.3 for Windows(SAS Institute Inc.,Cary,NC,USA.).Two-sided P<0.05 was considered statistically significant.Results1.Results on lifestyle and T2DMAmong 23,122 individuals,including 12,226 men(52.9%)and 10,896 women(47.1%),a total of 629 participants developed T2DM.The cumulative incidence rate was 2.72%,the incidence density was 7.1/1,000 person-years,and the median follow-up time was 3.9 years.For the associations between individual lifestyle factors and the risk of T2DM,after adjusting for multiple confounding factors,compared with participants with non-smoking,the HRs(95%CIs)were 1.29(0.96,1.73)for previously smoking and 1.28(1.05,1.57)for currently smoking,respectively,(P for trend=0.01).Compared with the low-risk alcohol group,the HRs(95%CIs)were 1.20(0.94,1.54)for 0.1-5 g/day,1.41(1.11,1.79)for 30-60 g/day in men and 20-60 g/day in women,and 1.02(0.64,1.65)for>60 g/day,respectively(P for trend=0.02).Compared with the BMI in the range of 18.5-23.9 kg/m~2,the HRs(95%CIs)were 0.76(0.28,2.08)for<18.5 kg/m~2,2.15(1.69,2.72)for 24-28 kg/m~2,and 4.02(3.14,5.16)for≥28 kg/m~2,respectively(P for trend<0.0001).The HR(95%CI)for comparing the extreme quartiles of physical activity(4th quartile vs.1st quartile)was 0.78(0.63,0.98),P for trend=0.02.For the“Health”dietary pattern score,compared with the lowest quartile,the HRs across the second,third and fourth quartiles were 0.94(0.73,1.23),0.84(0.67,1.07),and 0.79(0.62,1.01)(P for trend=0.03).In addition,the results did not see significant associations between the“Fruits and sweet”dietary pattern or the“Animal foods”dietary pattern and the onset of T2DM.By analyzing the association between the healthy lifestyle score and the incidence of T2DM,after adjusting for multiple confounding factors,compared with the unfavorable lifestyle group,the HRs(95%CIs)of the intermediate lifestyle group and the favorable lifestyle group were 0.66(0.50,0.71)and 0.34(0.24,0.48)(P for trend<0.0001).Through the interaction analysis,it was found that the healthy lifestyle score and age have an interactive effect on the occurrence of T2DM(P<0.001).When the age was under 40,a healthy lifestyle had a stronger protective effect on the occurrence of T2DM.Compared with the unfavorable lifestyle group,the HRs(95%CIs)of the intermediate lifestyle group and the favorable lifestyle group were 0.59(0.40,0.86)and 0.24(0.11,0.52).In a sensitivity analysis excluding participants that developed T2DM in the first year of follow-up,the similar results was seen.2.Results on lifestyle and prediabetesAmong 18,642 individuals,including 9,257 men(49.7%)and 9,385 women(50.3%),a total of 4,270 participants developed prediabetes.The cumulative incidence rate was 22.9%,the incidence density was 21.6/1,000 person-years,and the median follow-up time was 3.9 years.For the association between individual lifestyle factors and the risk of incidence prediabetes,after adjusting for multiple confounding factors,compared with participants with non-smoking,the HRs(95%CIs)of prediabetes were1.15(1.002,1.33)for previously smoking and 1.08(0.995,1.18)for currently smoking,respectively,(P for trend=0.046).Compared with the low-risk alcohol group,the HRs(95%CIs)were 1.08(0.98,1.19)for 0.1-5 g/day,1.04(0.97,1.12)for 30-60 g/day in men and 20-60 g/day in women,and 1.26(1.03,1.54)for>60 g/day,respectively(P for trend=0.02).Compared with the BMI in the range of 18.5-23.9 kg/m~2,the HRs(95%CIs)were 0.73(0.58,0.91)for<18.5 kg/m~2,1.28(1.19,1.38)for 24-28 kg/m~2,and 1.85(1.69,2.02)for≥28 kg/m~2,respectively(P for trend<0.0001).The HR(95%CI)for comparing the extreme quartiles of physical activity(4th quartile vs.1st quartile)was0.90(0.83,0.98),P for trend=0.04.The results did not observe significant associations between dietary patterns and the onset of prediabetes.By analysing the association between the healthy lifestyle score and the incidence of prediabetes,after adjusting for multiple confounding factors,compared with the unfavorable lifestyle group,the HRs(95%CIs)of the intermediate lifestyle group and the favorable lifestyle group were0.83(0.77,0.89)and 0.69(0.62,0.78)(P for trend<0.0001).Furthermore,when the age was under 40,a healthy lifestyle had a stronger protective effect on the occurrence of prediabetes(P for interaction<0.001):compared with the unfavorable lifestyle group,the HRs(95%CIs)of the intermediate lifestyle group and the favorable lifestyle group were 0.84(0.74,0.95)and 0.66(0.55,0.79).In a sensitivity analysis that excluded participants who developed T2DM in the first year of follow-up,the similar association was observed.Conclusions1.The data indicate that high physical activity and following healthy dietary pattern are associated with decreased risk of T2DM,whereas currently smoking,moderate-high alcohol consumption(30-60 g/day in men and 20-60 g/day in women),and high BMI are associated with increased risk of T2DM.In addition,compared with an unfavorable lifestyle,an intermediate lifestyle and a favorable lifestyle are associated with reduced risk of T2DM.Moreover,a healthy lifestyle score has a stronger protective effect on the occurrence of T2DM among participants aged<40 years than more than 40 years.2.The data indicate that previous smoking,high alcohol consumption(>60 g/day),and high BMI are positively associated with the risk of prediabetes,while high physical activity is inversely associated with the risk of prediabetes.In addition,following healthy diet pattern and“fruit and sweet”dietary pattern have inverse but non-significant associations with the risk of prediabetes.In comparison with an unfavorable lifestyle,an intermediate lifestyle and a favorable lifestyle are associated with reduced risk of prediabetes.Moreover,a healthy lifestyle has a stronger protective effect on the occurrence of prediabetes among participants aged under 40 years.3.Adherence to a healthy lifestyle is associated with reduced risks of T2DM and prediabetes in the general adult population.These results suggest that in order to prevent and control the occurrence of T2DM and even prediabetes,it is necessary to maintain a favorable lifestyle.Future intervention trials are needed to verify the findings of the cohort study. |
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