Association Of Age At Menarche With Blood Glucose In Middle-Aged And Elderly Women

BackgroundDiabetes Mellitus(DM)is a kind of metabolic disease caused by the interaction of many factors(including environmental factors,genetic factors,behavioral factors)It is characterized by hyperglycemia,which can cause disorders of the metabolism of water,electrolyte,fat,and protein.The pathologic mechanism of diabetes is the dysfunction and/or structural damage of islet β-cell,which leads to reduced insulin sensitivity and relatively or absolutely insufficient insulin secretion.Diabetes is currently divided into type 1 diabetes and type 2 diabetes.Type 1 diabetes is characterized by the body’s inability to produce enough insulin.Type 2 diabetes is characterized by the body’s inability to use insulin effectively.With the economic development,the acceleration of urbanization,the aging of the population,and the changes in life style(such as diet style),the prevalence of diabetes has shown an upward trend year by year.Diabetes has caused a great social,economic,and healthy burden and has become one of the major public health challenges in most countries.Previous studies have pointed that premature age at menarche may increase the risk of diabetes,but the biological mechanism of this association is still controversial.Firstly,premature age at menarche in women may indicate higher levels of childhood obesity,as well as long-term exposure to estrogen and adrenal steroid hormones.These may affect the body fat metabolism of adults.In addition,a genetic locus of age at menarche is associated with the BMI in adults.Therefore,some studies support that age at menarche may affect the risk of adult obesity and ultimately lead to an increased risk of adult diabetes.However,some studies did not find an association of age at menarche with diabetes.But other studies found that the association could exist independently of obesity.At present,there are relatively few studies exploring the relationship between age at menarche and blood glucose level.In view of the inconsistency of previous studies,this study was designed to explore the type and strength of the relationship between age at menarche and fasting plasma glucose(FPG)and HemoglobinA1c(HbA1c)in middle-aged and elderly women.Besides,this study can help to explore the effect of age at menarche on the risk of diabetes in the future and provide a theoretic basis for the risk identification and prompt intervention of diabetes in middle-aged and elderly women.Objectives1.To estimate the changing trend of age at menarche in different groups of birth age.2.To study risk factors that affect the level of blood glucose.3.To explore the type and strength of the relationship between age at menarche and blood glucose.4.To analyze whether there is an interaction between age at menarche and dyslipidemia on blood glucose.MethodsIn this study,a total of 5119 middle-aged and elderly women were included from the 2011 baseline survey(3677 participants)and the 2015 survey(1442 participants)of the China Health and Retirement Longitudinal Study.Firstly,the method of descriptive analysis was used to initially study the basic characteristics of the total population and subgroups by survey year.Linear regression analysis and line graph were used to characterize changing trend of age at menarche.Univariate and multivariate linear regression respectively were introduced to estimate influence factors of blood glucose(divided into FPG and HbAlc).Besides,restricted cubic splines were used to determine whether there was a non-linear correlation between age at menarche and blood glucose.For the non-linear relationships,piecewise linear regression was performed to analyze thresholds.For the linear relationship,weighted multiple linear regression was used to analyze the strength of this relationship.Finally,age at menarche was assigned to different groups according to the quartile.Multiple linear regressions were used to analyze whether there was an interaction between age at menarche and dyslipidemia on blood glucose.The statistical software involved in this study included STATA16.0(Stata Corporation,College Station,TX,USA)and R language 3.6.3 software.All regression models considered the sampling weight,and P<0.05 on both sides was considered statistically significant.Results1.The linear regression analysis showed that age at menarche decreased with the longitudinal change of age at birth(P<0.001).2.Multiple linear regression analysis showed that age at 55-64 years old(FPG:β=2.317,P=0.016;HbA1c:β=0.107,P<0.001),age at 65-74 years old(FPG:β=5.080,P=0.003;HbAlc:β-0.167,P<0.001),age at menarche(FPG:β=-0.468,P=0.026;HbAlc:β=-0.012,P=0.039),dyslipidemia(FPG:β=7.156,P<0.001;HbAlc:β=0.078,P=0.004)and the 2015 survey year(FPG:β=-8.944,P<0.001;EHAlc:β=0.673,P<0.001)were significantly associated with FPG and HbAlc3.After adjusting for potential confounders of place of residence,age,marital status,education level,smoking,drinking,survey year,hypertension,dyslipidemia,depression,menopause,and obesity,there was a linear association of age at menarche with FPG(β2=-0.815,P=0.154)and HbAlc(β2=0.003,P=0.837)in middle-aged and elderly women4.After adjusting for potential confounding factors involved in this study,age at menarche was significantly,negatively,and linearly associated with FPG(β=-0.468,P=0.026)and HbA1c(β=-0.012,P=0.039)5.The analysis of the interaction effect showed that the additive interaction between age at menarche and dyslipidemia on blood glucose was not statistically significant.ConclusionsIn middle-aged and elderly women,age at menarche presents a downtrend with the growth of age at birth.Besides,age at menarche is linearly and negatively correlated with FPG and HbAlc.After adjusting for the variable of obesity,the negative linear relationship between age at menarche and blood glucose is still significant.It suggests that age at menarche may affect the blood glucose level in adult women independently of the obesity status of middle-aged and elderly women.