Early menarche increases the risk of Type 2 diabetes in young and middle-aged Korean women

Trends in the prevalence of obesity, overweight, and thinness among schoolchildren aged 7-14 years from southern Brazil (2002-2019)

OBJECTIVE

To analyze the obesity, overweight, and thinness trends among Brazilian schoolchildren by sex, age group, and type of school according to World Health Organization (WHO) and International Obesity Task Force (IOTF) criteria.

METHODS

We conducted four surveys between 2002 and 2018/19 involving schoolchildren aged 7-14 years from a state capital in southern Brazil. Weight status was classified using both WHO and IOTF criteria.

RESULTS

In the total sample, obesity prevalence based on the IOTF and the WHO criteria were 72% and 44% higher in 2018/19 compared with 2002, respectively. Over the whole period, the obesity prevalence increased among children (WHO: 10.1% vs. 14.1%; IOTF: 5.0% vs. 8.3%), and those from public schools (WHO: 10.5% vs. 16.4%; IOTF: 5.6% vs. 10.1%). There was no significant reduction in thinness prevalence over the analyzed period.

CONCLUSION

Obesity prevalence remains on an upward trend in a state capital in southern Brazil, especially among children from public schools. A higher prevalence of overweight and obesity was observed using the WHO criteria compared with IOTF criteria.

Menarche age and the risk of diabetes: A cross-sectional study in South-Eastern Iran

Background and Aims

Diabetes is a major public health problem worldwide. This study aimed to determine the relationship between menarche age and overt diabetes in southeast Iran.

Methods

This cross-sectional study was conducted on 6094 eligible women between the ages of 35 and 70 participating in the Zahedan Adult Cohort Study. Demographic and background data, fertility, anthropometry, and disease history were collected based on a questionnaire. Menarche age was classified into five categories (under 12 years, 12, 13, 14, 15 years and more). Diabetes is defined as a blood sugar of 126 or more according to the definition by the American Diabetes Association. Data analysis was done using SPSS 26 software. Descriptive analysis was performed with frequency, percentage, mean, and standard deviation; and analytical analysis using chi-square and logistic regression tests. The significance level in this study was p < 0.05.

Results

The participants' mean age was 49.41 ± 8.88, and the mean age at menarche was 13 ± 1.49. 22.8% (1389 women) of participants with diabetes and 77.2% (4705 women) did not have diabetes. The findings showed that the chance of developing diabetes in women with a menarche age <12 years was significantly higher than in women with a menarche age of 13 years (reference) (OR = 1.23, 95% CI: 0.96, 1.51). This relationship was significant after adjusting variables such as body mass index, education level, fertility factors, history of diabetes, and reproductive diabetes (OR = 1.21, 95% CI: 0.90, 1.44, p = 0.04).

Conclusion

Our findings suggest that young age at menarche may be a risk factor for diabetes in adulthood. Further prospective studies are needed to confirm our findings. However, it is suggested to pay attention to it in diabetes screening so that, if possible, by identifying people at risk and implementing prevention programs, the adverse consequences of diabetes can be reduced.

Ideal Cardiovascular Health Metrics Attenuated Association of Age at Menarche With Type 2 Diabetes in Rural China

Objective: It is not clear whether ideal cardiovascular health (ICH) metrics have an impact on the association between age at menarche and type 2 diabetes (T2DM) in rural postmenopausal Chinese women.

Methods: In all, 15,450 postmenopausal women were enrolled from the Henan Rural Cohort study. Logistic regression models and interaction plots were used to analyze associations between age at menarche, ICH metrics and T2DM and interactive effects.

Results: Age at menarche was inversely associated with risk of T2DM, with adjusted OR of 1.224, 1.116, 1.00 and 0.971, 0.850 for those with age at menarche ≤13, 14, 15–16 (reference), 17, and ≥18 years, respectively, and each year of delay in menarche age correlated with a 5.1% lower risk of T2DM. Negative interaction effects of age at menarche and number of ICH metrics on the risk of T2DM was observed.

Conclusion: Meeting more ICH metrics might attenuate the association between early menstrual age and increased risk of T2DM, implying that meeting a higher number of ICH metrics may be an effective way to prevent T2DM for women of early menarche age.

Age at menarche, ideal cardiovascular health metrics, and risk of diabetes in adulthood: Findings from the REACTION study

BACKGROUND

Age at menarche was reported to be associated with the risk of diabetes. However, the impact of ideal cardiovascular health metrics (ICVHMs) on the association between age at menarche and adulthood diabetes risk was unclear.

METHODS

We included 121 431 women from the nationwide, population-based cohort of the REACTION study (Risk Evaluation of Cancers in Chinese Diabetic Individuals: a Longitudinal Study). The diagnosis of diabetes was based on the oral glucose tolerance test (OGTT) and glycosylated hemoglobin (HbA1c) measurement. Logistic regression and multiplicative interaction analysis were conducted to investigate the potential interaction effect between age at menarche and ICVHMs on the development of diabetes.

RESULTS

The multivariable-adjusted odds ratios of diabetes across categories of age at menarche (<14, 14-17, and > 17 years) were 1.22 (95% confidence interval [CI]: 1.17, 1.28), 1.00 (reference), and 0.89 (95% CI: 0.85, 0.93), respectively. In subgroup analysis, significant interactions were detected between total cholesterol/blood pressure levels and age at menarche regarding the risk of diabetes (P for interaction = .0091 and .0019, respectively). The increased risk associated with age at menarche <14 years was observed in participants with three or fewer ICVHMs, but not in women with four or more ICVHMs (P for interaction = .0001).

CONCLUSIONS

Age at menarche was inversely associated with the risk of diabetes in adulthood in Chinese women, and it appeared to be modified by the presence of ICVHMs. Further studies are needed to clarify the precise interrelationship and the generalizability of our results.

Factors influencing peak bone mass gain

Bone mass is a key determinant of osteoporosis and fragility fractures. Epidemiologic studies have shown that a 10% increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50%. Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood. Race, gender, and family history (genetics) are responsible for the majority of PBM, but other factors, such as physical activity, calcium and vitamin D intake, weight, smoking and alcohol consumption, socioeconomic status, age at menarche, and other secondary causes (diseases and medications), play important roles in PBM gain during childhood and adolescence. Hence, the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people, and thus to reduce the low bone mass or osteoporosis risk in later life. This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

Early menarche and its consequence in Korean female: reducing fructose intake could be one solution

The mean age at menarche (AAM) of Korean females has been rapidly decreasing over the last 50 years; currently, the prevalence of early menarche (<12 years) is 22.3%. Female adolescents who experience early menarche are known to be at greater risk of psychosocial and behavioral problems along with several physical health problems such as menstrual problems. They also tend to achieve a shorter final height and develop obesity. Population-based Korean studies have shown a strong association between early menarche and the risk of obesity, insulin resistance, metabolic syndrome, nonalcoholic fatty liver disease, diabetes, breast cancer, and cardiovascular disease in adulthood. Although the exact mechanism of how early menarche causes cardiometabolic derangement in later adulthood is unknown, childhood obesity and insulin resistance might be major contributors. Recent studies demonstrated that an excessive consumption of fructose might underlie the development of obesity and insulin resistance along with an earlier AAM. A positive association was observed between sugar-sweetened beverages (a major source of fructose) intake and obesity, metabolic syndrome, insulin resistance, and cardiometabolic risk in Korean females. In pediatrics, establishing risk factors is important in preventing disease in later life. In this regard, early menarche is a simple and good marker for the management of cardiometabolic diseases in adulthood. Decreasing one's fructose intake might prevent early menarche as well as the development of obesity, insulin resistance, and cardiometabolic diseases.

Adiposity and insulin resistance as mediators between age at menarche and type 2 diabetes mellitus

OBJECTIVE

This study aimed to explore the association between age at menarche and type 2 diabetes mellitus (T2DM) and whether the association is mediated by adiposity and insulin resistance (IR) in rural Chinese women.

METHODS

This cross-sectional study analyzed data for 7,460 women (median age 56 y) from a rural Chinese area from 2013 to 2014. Data were collected by standardized interviews and anthropometric and laboratory measurements. Adiposity was measured by body mass index (BMI), and IR was measured by the homeostasis model assessment of IR (HOMA-IR) index. Multivariate logistic regression models were used to estimate odds ratios (ORs) and 95% confidence limits (CLs) for the association between age at menarche and T2DM. Mediation analysis was performed to explore the contribution of BMI and HOMA-IR to the association between age at menarche and T2DM.

RESULTS

Among 7,460 women, 840 (11.26%) had T2DM. After adjusting for potential confounding factors, the odds of T2DM with the latest age at menarche 18 years or older versus 13 years was reduced (OR = 0.65, 95% CL: 0.47, 0.91), and age at menarche was negatively associated with T2DM (per additional year of menarche, OR = 0.95, 95% CL: 0.91, 0.99). BMI and HOMA-IR completely mediated the association between age at menarche and T2DM (total indirect effect: OR = 0.973, 95% CL: 0.961, 0.986; direct effect: OR = 0.974, 95% CL: 0.930, 1.021).

CONCLUSIONS

Late menarche may be negatively associated with T2DM. The potential mechanism is adiposity and IR completely mediating the association between age at menarche and T2DM.

Negative Effects of Age at Menarche on Risk of Cardiometabolic Diseases in Adulthood: A Mendelian Randomization Study

CONTEXT

Observational studies have demonstrated that early menarche is associated with cardiometabolic diseases, but confounding factors make it difficult to infer causality.

OBJECTIVE

We used Mendelian randomization (MR) to examine whether age at menarche (AAM) is causally associated with type 2 diabetes (T2D), coronary artery disease (CAD) and cardiometabolic traits.

DESIGN AND METHODS

A 2-sample MR analysis was conducted using genome-wide association study (GWAS) summary statistics from the Diabetes Genetics Replication and Meta-analysis (DIAGRAM) consortium (n = 159 208) for T2D and the Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease Genetics (CARDIoGRAMplusC4D) consortium (n = 184 305) for CAD. We used 122 instrumental variables (IVs) extracted from a published GWAS meta-analysis incorporating 182 416 women to determine the causal effect of AAM on cardiometabolic diseases, treating childhood and adult body mass index (BMI) as the confounders. Sensitivity analyses were also performed to detect the pleiotropy of the IVs.

RESULTS

Employing the MR approach, we found that later AAM was associated with decreased risk of CAD (OR, 0.92 [95% CI, 0.88-0.96]; P = 2.06 × 10-4) in adults, as well as lower blood levels of log fasting insulin, log homeostatic model assessment of insulin resistance (HOMA-IR), log HOMA of β-cell function (HOMA-B), triglycerides, and diastolic blood pressure, but higher blood level of high-density lipoprotein. However, the associations were substantially attenuated after excluding BMI-related variants. MR analyses provide little evidence on the causal effect between AAM and T2D.

CONCLUSIONS

Our findings showed that AAM did not appear to have a causal effect on the risk of cardiometabolic diseases in adult life, as their associations observed in epidemiological studies might be largely mediated through excessive adiposity. We propose adiposity might be a primary target in future intervention strategy.

Association of puberty timing with type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Emerging studies have investigated the association between puberty timing, particularly age at menarche (AAM), and type 2 diabetes. However, whether this association is independent of adiposity is unclear. We aimed to systematically review published evidence on the association between puberty timing and type 2 diabetes (T2D) or impaired glucose tolerance (IGT), with and without adjustment for adiposity, and to estimate the potential contribution of puberty timing to the burden of T2D in the United Kingdom (UK).

METHODS AND FINDINGS

We searched PubMed, Medline, and Embase databases for publications until February 2019 on the timing of any secondary sexual characteristic in boys or girls in relation to T2D/IGT. Inverse-variance-weighted random-effects meta-analysis was used to pool reported estimates, and meta-regression was used to explore sources of heterogeneity. Twenty-eight observational studies were identified. All assessed AAM in women (combined N = 1,228,306); only 1 study additionally included men. In models without adjustment for adult adiposity, T2D/IGT risk was lower per year later AAM (relative risk [RR] = 0.91, 95% CI 0.89-0.93, p < 0.001, 11 estimates, n = 833,529, I2 = 85.4%) and higher for early versus later menarche (RR = 1.39, 95% CI 1.25-1.55, p < 0.001, 23 estimates, n = 1,185,444, I2 = 87.8%). Associations were weaker but still evident in models adjusted for adiposity (AAM: RR = 0.97 per year, 95% CI 0.95-0.98, p < 0.001, 12 estimates, n = 852,268, I2 = 51.8%; early menarche: RR = 1.19, 95% CI 1.11-1.28, p < 0.001, 21 estimates, n = 890,583, I2 = 68.1%). Associations were stronger among white than Asian women, and in populations with earlier average AAM. The estimated population attributable risk of T2D in white UK women due to early menarche unadjusted and adjusted for adiposity was 12.6% (95% CI 11.0-14.3) and 5.1% (95% CI 3.6-6.7), respectively. Findings in this study are limited by residual and unmeasured confounding, and self-reported AAM.

CONCLUSIONS

Earlier AAM is consistently associated with higher T2D/IGT risk, independent of adiposity. More importantly, this research has identified that a substantial proportion of T2D in women is related to early menarche, which would be expected to increase in light of global secular trends towards earlier puberty timing. These findings highlight the need to identify the underlying mechanisms linking early menarche to T2D/IGT risk.

Early Menarche is a Risk Factor for Short Stature in Young Korean Females: An Epidemiologic Study

OBJECTIVE

To assess the association between age at menarche and adult height [and body mass index (BMI)] in young Korean females and also to investigate whether early menarche (<12 years) is a risk factor for short stature and obesity in young Korean females.

METHODS

Data on 1148 females aged 18-30 years and 612 mother (612 pairs of mothers and daughters) from the 6^th Korea National Health and Nutrition Examination Survey (2013-2015) were analyzed.

RESULTS

Among 1148 females, 256 (22.3%) had early menarche. Their stature was approximately 0.445 cm shorter when menarche had occurred one year earlier. The prevalence of short stature (≤153 cm) and obesity (BMI ≥25) was higher in females with early menarche compared to those with later menarche (short stature: 10.5% vs 6.4%, obesity; 20.7% vs 13.1%, all p<0.001). In multivariate regression, the odds ratio (OR) for short stature was 2.62 [95% confidence interval (CI): 1.26-5.44] after adjusting for current age and mother’s height. OR for obesity was 1.74 (95% CI: 0.98-3.07) after adjusting for age and maternal BMI.

CONCLUSION

Final height in girls is influenced by age of menarche. Early menarche increased the risk for adult short stature in young Korean females.

Declining age at menarche in Indonesia: a systematic review and meta-analysis

BACKGROUND

There has been much research on the average age at menarche onset. In higher income countries the lowering in average age at menarche is earlier than in middle-income countries and lower income countries. Indonesia as a middle-income country also has some research experience related to the average age at menarche for girls.

OBJECTIVES

This study aimed to review the lowering of the average age at menarche in Indonesia and to predict changes in average age at menarche.

METHODS

This study provides a systematic review and meta-analysis using references from Google Scholar, PubMed and Popline databases on the trend of age at menarche in Indonesia and other data sources from local and national survey reports. Metaprop command in STATA was used to do the meta-analysis of proportion of early age at menarche and time series with auto-regressive integrated moving average (ARIMA) models were used in analyzing the trend and predicting the age at menarche.

RESULTS

The results show that in Indonesia the timing of age at menarche onset has significantly lowered during the 40 years before 2010. There was meaningful decrease of age at menarche, which changed from 14.43 years [confident interval (CI) 95%: 14.42, 14.44] to 13.63 years (CI95%: 13.63, 13.64). Using the ARIMA model, mean age at menarche onset for the next year predicted that the coefficient regression would be -0.0245 (CI95%: -0.0275, -0.0215). The predicted average age at menarche shows a decrease of 0.0245 years (8-9 days) each year.

CONCLUSION

The findings indicate a significant lowering of age at menarche in Indonesian girls that has continued as a predictable trend through time until the present, paralleling recent socioeconomic changes. These predictions provide key indicators of a girl's future healthy transition from childhood into young adulthood.

Impact of age at menarche on obesity and glycemic control in Japanese patients with type 2 diabetes: Fukuoka Diabetes Registry

AIMS/INTRODUCTION

A younger age at menarche is associated with obesity and type 2 diabetes in adult life. The impact of early-onset menarche on obesity and glycemic control in type 2 diabetes has not been investigated. The present study examined the relationship between age at menarche and obesity and glycemic control in type 2 diabetes.

MATERIALS AND METHODS

A total of 2,133 patients with type 2 diabetes aged ≥20 years were divided into groups according to age at menarche (≤11, 12, 13, 14 and ≥15 years). A retrospective cohort study examined the association of menarcheal age with adiposity and hemoglobin A1c .

RESULTS

Age at menarche was inversely associated with body mass index (BMI) and abdominal circumference (P < 0.001). Each 1-year decrease in age at menarche was associated with a 0.25-kg/m2 and 0.6-cm increase in BMI and abdominal circumference, respectively, using a multivariate-adjusted model. Odds ratios for obesity and abdominal obesity significantly increased in participants with age at menarche ≤11 years after multivariable adjustments when age at menarche of 13 years was used as the reference (odds ratio 1.95, 95% CI 1.33-2.88, odds ratio 1.95, 95% CI 1.32-2.87, respectively). Younger age at menarche was significantly associated with higher hemoglobin A1c (P < 0.001); however, the association was not statistically significant after adjusting for BMI.

CONCLUSIONS

Age at menarche of ≤11 years was associated with obesity after adjusting for confounding factors, and poor glycemic control associated with high BMI in type 2 diabetes. Age at menarche should be considered during clinical assessments.

Age at Menarche and Cardiometabolic Health: A Sibling Analysis in the Scottish Family Health Study

BACKGROUND

Previous studies of age at menarche and cardiometabolic health report conflicting findings, and only a few could account for childhood characteristics. We aimed to estimate the associations of age at menarche with cardiovascular risk factors in unrelated women and within sister groups, under the assumption that within-sibship estimates will be better adjusted for shared genetics and early life environment.

METHODS AND RESULTS

Our study included 7770 women, from 5984 sibships, participating in the GS:SFHS (Generation Scotland: Scottish Family Health Study). We used fixed- and between-effects linear regression to estimate the associations within sister groups and between unrelated individuals, respectively. Within sibships, the mean difference between sisters with early menarche (≤11 years) and sisters with menarche at 12 to 13 years was 1.73 mm Hg (95% confidence interval [CI], -0.41 to 3.86) for systolic blood pressure, 1.26 mm Hg (95% CI, -0.02 to 2.55) for diastolic blood pressure, -0.06 nmol/L (95% CI, -0.11 to -0.02) for high-density lipoprotein, 0.20 nmol/L (95% CI, 0.08-0.32) for non-high-density lipoprotein, -0.34% (95% CI, -1.98 to 1.30) for glucose, 1.60 kg/m² (95% CI, 0.92-2.28) for body mass index, and 2.75 cm (95% CI, 1.06-4.44) for waist circumference. There was weak evidence of associations between later menarche (14-15 or ≥16 years) and lower body mass index, waist circumference, and blood pressure. We found no strong evidence that estimates from within- and between-sibship analyses differed (all P values >0.1). The associations with other cardiovascular risk factors were attenuated after adjustment for adult body mass index.

CONCLUSIONS

Our results suggest that confounding by shared familial characteristics is unlikely to be a major driver of the association between early menarche and adverse cardiometabolic health but do not exclude confounding by individual-level characteristics.

Age at Menarche and Incidence of Diabetes: A Prospective Study of 300,000 Women in China

Previous studies of predominantly Western populations have reported inconsistent associations between age at menarche and risk of diabetes. We examined this relationship among Chinese women, who generally experience menarche at a later age than Western women. In 2004–2008, China Kadoorie Biobank recruited 302,632 women aged 30–79 years from 10 areas across China, and recorded 5,391 incident cases of diabetes during 7 years of follow-up among 270,345 women without baseline diabetes, cardiovascular disease or cancer. Cox regression models yielded adjusted hazard ratios for incident diabetes associated with age at menarche. Overall, the mean age at menarche was 15.4 years, and decreased across successive generations. Age at menarche was linearly and inversely associated with incident diabetes, with adjusted hazard ratio of 0.96 (95% confidence interval (CI): 0.94, 0.97) per year delay. Hazard ratios were greater in younger generations (for women born in the 1960s–1970s, hazard ratio (HR) = 0.93, 95% CI: 0.90, 0.97; for women born in the 1950s, HR = 0.95, 95% CI: 0.93, 0.98; and for women born in the 1920s–1940s, HR = 0.97, 95% CI: 0.95, 0.99). Further adjustment for adulthood body mass index significantly attenuated the association (HR = 0.99, 95% CI: 0.97, 1.00), especially among those born before 1950 (HR = 1.00, 95% CI: 0.97, 1.02). Much of the inverse association between age at menarche and incident diabetes was mediated through increased adiposity associated with early menarche, especially in older generations.

Early menarche is associated with non-alcoholic fatty liver disease in adulthood

BACKGROUND

The aim of this study was to examine the association between early menarche (<12 years) and non-alcoholic fatty liver disease (NAFLD) in premenopausal women and to explore whether it is mediated by adult obesity and insulin resistance.

METHODS

We analyzed data of premenopausal women, aged ≥15 years, from the Korea National Health and Nutrition Examination Survey (2007-2009). We divided the women into three groups: early menarche, reference (12.00-15.99 years), and late menarche. The presence of NAFLD was determined using hepatic steatosis index >36.0.

RESULTS

Of the 4,387 women evaluated, 673 (15.4%) met the criteria for NAFLD. The prevalence of NAFLD was higher in both women with early and late menarche compared with the reference (early, 23.4%; reference, 14.0%; late, 19.9%, P < 0.001). After adjustment of confounders including age, the OR for NAFLD in early menarche compared with the reference was 3.04 (95%CI: 1.99-4.65). Further adjustment of mediators, such as central obesity or insulin resistance, attenuated the association to 1.91-2.17. There was no association, however, between late menarche and NAFLD after adjustment of confounders.

CONCLUSIONS

Early menarche was associated with an increased risk of NAFLD in young and middle-aged premenopausal Korean women.

Effects of early menarche on physical and psychosocial health problems in adolescent girls and adult women

The menarcheal age of Korean women has been rapidly decreasing for the last 50 years, and the average menarcheal age of women born in the 1990s is approaching 12.6 years. In addition, interest in early puberty has been increasing recently owing to the rapid increase in precocious puberty. Generally, out of concern for short stature and early menarche, idiopathic central precocious puberty in female adolescents is treated with gonadotropin-releasing hormone analogs. Studies to date have described the association between early menarche and psychosocial problems such as delinquency and risky sexual behavior, as well as physical health problems such as obesity, diabetes, cardiovascular diseases, and breast cancer throughout the lifespan of women. However, the pathophysiological mechanism underlying this association has not been clarified thus far. In this article, we review and discuss the existing literature to describe the current understanding of the effects of early menarche on the physical and psychosocial health of adolescent girls and adult women.

The effect of early menarche on the sexual behaviors of Korean female adolescents

PURPOSE

This study examined the relationships between early menarche and sexual behaviors among Korean female adolescents.

METHODS

We analyzed data from the eighth Korea Youth Risk Behavior Web-based survey that was conducted on female high school students in grades 10-12. The survey included 17,867 students, and 974 students were assigned to the early menarche group because they had experienced menarche when they were in grade four or below, and 16,893 students were assigned to the normal menarche group because they had experienced menarche during or after grade five. The characteristics of the sexual behaviors in the early menarche and normal menarche group were analyzed.

RESULTS

The early menarche group was at a higher risk of intersexual kissing or petting (odds ratio [OR], 1.54; 95% confidence interval [CI], 1.28-1.87), intersexual intercourse (OR, 2.35; 95% CI, 1.65-3.36), homosexual kissing or petting (OR, 3.53; 95% CI, 2.22-5.59), homosexual intercourse (OR, 7.70; 95% CI, 4.04-14.66), being the victim (OR, 2.89; 95% CI, 1.98-4.22) or the assailant (OR, 13.55; 95% CI, 6.61-27.78) of sexual assaults, intercourse without any contraception (OR, 1.92; 95% CI, 1.06-3.46), and pregnancy (OR, 5.72; 95% CI, 2.31-14.15) than the normal menarche group.

CONCLUSION

Early menarche is associated with risky sexual behaviors among adolescent females; therefore, developing comprehensive sexual health education programs and tools for early intervention are required for children who are expected to experience early menarche.

Milk--A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

Based on own translational research of the biochemical and hormonal effects of cow's milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1) essential branched-chain amino acids (BCAAs); (2) glutamine; (3) palmitic acid; and (4) bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER) stress and drives an aimless quasi-program, which promotes aging and age-related diseases.

Association between age at menarche and diabetes in Korean post-menopausal women: results from the Korea National Health and Nutrition Examination Survey (2007-2009)

Early menarche is known to be associated with diabetes, however this association remains controversial. Our study aimed to investigate the possible association between age at menarche and diabetes prevalence in post-menopausal Korean women. This study included 3,254 post-menopausal Korean women aged 50-85 years from the Korea National Health and Nutrition Examination Survey IV (KNHANES 2007-2009). Logistic regression analyses were used to estimate odds ratios (ORs) for diabetes prevalence. Levels of biochemical markers were compared according to groups by age at menarche. Women in the earlier menarche age group (10-12 years) showed higher levels of fasting blood glucose (FBG) and scores of homeostatic model assessment in the insulin resistance (HOMA-IR) index than other groups (p <0.05). After adjusting for potential confounding factors, early age at menarche was significantly associated with a higher prevalence of diabetes (OR 1.86, 95% confidence intervals [CI] 1.07-3.23). The observed association remained significant despite additional adjustment for body mass index and waist circumference (OR 1.82, 95% CI 1.03-3.23) and despite further adjustments for FBG levels and HOMA-IR index (OR 2.25, 95% CI 1.11-4.55). Our findings strengthen the hypothesis that younger age at menarche is associated with increased diabetes prevalence in the Korean population.