Nutritional status and age at menarche in Amazonian students.

OBJECTIVES: Age at menarche (MA) is a proxy for biological maturation and a parameter of socioeconomic changes. Worldwide, anticipation of menarche is associated with nutritional transition and excess weight. The objective of this study was to evaluate the MA in Amazonian students and its association with nutritional status, ethnicity, and socioeconomic level. METHODS: Cross-sectional study with 1,017 students aged 6 to 17 living in the city of Manaus, Brazil. MA was analyzed by status quo and recall; its association with body mass index (BMI), race, socioeconomic status, and adult height was examined. RESULTS: 559 (51.9%) participants had already experienced menarche. In 91.7%, menarche occurred between 10 and 14 years of age; the mean age at the onset of menarche was 11.9 years. Overweight (11.6 years) and obese (11.4 years) participants reached menarche earlier than those with normal weight (12 years) and lean (12.7 years) participants. The associations between MA and nutritional status showed that overweight and obesity are risk factors for the early occurrence of menarche. MA was not associated with socioeconomic status/parental education or race. However, excess weight was associated with earlier MA in all races and social classes. The adult height was slightly lower in girls with menarche before 12 years old (157.9 vs 159.4 cm). CONCLUSION: Regardless of socioeconomic level or ethnicity, excess weight was associated with earlier menarche in Amazonian students.

Prepubertal Internalizing Symptoms and Timing of Puberty Onset in Girls.

Stressful environments have been associated with earlier menarche. We hypothesized that anxiety, and possibly other internalizing symptoms, are also associated with earlier puberty in girls. The Lessons in Epidemiology and Genetics of Adult Cancer From Youth (LEGACY) Girls Study (2011-2016) included 1,040 girls aged 6-13 years at recruitment whose growth and development were assessed every 6 months. Prepubertal maternal reports of daughter's internalizing symptoms were available for breast onset (n = 447), pubic hair onset (n = 456), and menarche (n = 681). Using Cox proportional hazard regression, we estimated prospective hazard ratios and 95% confidence intervals for the relationship between 1 standard deviation of the percentiles of prepubertal anxiety, depression, and somatization symptoms and the timing of each pubertal outcome. Multivariable models included age, race/ethnicity, study center, maternal education, body mass index percentile, and family history of breast cancer. Additional models included maternal self-reported anxiety. A 1-standard deviation increase in maternally reported anxiety in girls at baseline was associated with earlier subsequent onset of breast (hazard ratio (HR) = 1.22, 95% confidence interval (CI): 1.09, 1.36) and pubic hair (HR = 1.15, 95% CI: 1.01, 1.30) development, but not menarche (HR = 0.94, 95% CI: 0.83, 1.07). The association of anxiety with earlier breast development persisted after adjustment for maternal anxiety. Increased anxiety in young girls may indicate risk for earlier pubertal onset.

Secular trends in age at menarche in 20th century Mexico: Differences by ethnicity, area of residency, and socioeconomic status.

OBJECTIVES: This study aims to assess the secular trend in age at menarche (AAM) in Mexico over the 20th century, and compare the patterns according to area of residence (rural/urban), socioeconomic status (SES), and ethnicity (indigenous/nonindigenous). METHODS: Data on AAM from 24 380 women aged ≥20 years born between 1906 and 1986 were obtained from the Mexican National Health and Nutrition Survey 2006. Birth cohorts were compared to test for a secular trend and differences in mean AAM by area of residence, SES, and ethnicity were evaluated using the Welch test for heterogeneous variances followed by Tamhane T2 for post hoc comparisons. RESULTS: Mean AAM declined from 13.3 years among Mexican women born before the 1940s to 12.56 years among those born in the 1980s. Across birth cohorts, urban women had significantly earlier AAM than their rural counterparts. Nonindigenous urban women reached menarche the earliest and rural indigenous women the latest of all groups. Nonindigenous urban residents experienced a comparatively earlier decline, while that for the indigenous rural women occurred last. High SES women reached menarche the earliest and low SES women the latest. The historical decline in AAM for high and medium SES groups occurred relatively early, whereas that for the low SES occurred last. CONCLUSIONS: Mean AAM was associated with area of residence, ethnicity, and SES. Our findings indirectly suggest that advances in living conditions experienced in Mexico during the 20th century appear to have been insufficient to overcome the social and biological inequalities accumulated over centuries in some groups.

The relationship among the age at menarche, anthropometric characteristics, and socio-economic factors in Bengali girls from Kolkata, India.

OBJECTIVES: The aim of the study was to measure the causal effect of selected socio-economic factors and anthropometrical characteristics on the menarche occurrence. METHODS: The sample consisted of 2195 Bengali girls (aged 7-21) from middle-class families, from Kolkata city, India. The age at menarche was recorded from the retrospective data and status quo method. The causal effect of anthropometric and socio-economic variables on menarche occurrence was estimated by the nonparametrical analysis of survival probability (survival random forest). RESULTS: In the examined cohort menarche occurred, on average, at 11.8 years of age. The probability of menarche occurrence amplified with the increasing values of factors such as body mass index, height-for-age z-scores, number of family members, household rooms, and toilets, but decreased when expenditures increased. The relation maintained a similar pattern of causal effect with girls' age. CONCLUSIONS: A complex pattern of relationship among sexual development, physique, and socio-economic characteristics was defined. The tendency toward early menarche, along with the observed causal relationships indicate that the analyzed sample is nearing the characteristics and standards of living noted in other middle and even high-income countries in the world.

Night Shift Work and Risk of Breast Cancer in Women.

BACKGROUND: Night shift work involving circadian disruption has been associated with increased breast cancer rates in some epidemiological studies, but the evidence is still on debate. AIM OF THE STUDY: The objective of this study is to assess the association between night shift work and breast cancer in Mexican women. METHODS: A Case-control study was conducted with incident cases of breast cancer at the Instituto de Seguridad Social del Estado de México y Municipios. Cases were interviewed about past exposures prior to the final diagnosis. Controls were women without breast cancer matched on multiple sociodemographic characteristics. RESULTS: 101 cases and 101 matched controls were interviewed; this small sample size provided consistent, but wide estimates of the assessed associations. The multivariate conditional logistic regression showed that breast-feeding was associated with reduced risk for breast cancer (OR 0.12; 95% CI: 0.02-0.60); women who experienced early menarche (12 years) were more likely to develop breast cancer (OR 18.58; 95% CI 18: 2.19-148). Women who worked at night were more likely to develop breast cancer compared to women who never did (OR = 8.58; 95% CI: 2.19-33.8). CONCLUSIONS: Our results are consistent with studies from other countries, which positively associated night shift work with breast cancer.

Is menarche occuring earlier among Lebanese girls?

BACKGROUND: Early menarche is associated with increased risks for several diseases such as cardiovascular diseases and breast cancer. This analysis aimed at generating evidence on a historical trend towards younger age at menarche among Lebanese girls. METHODS: A secondary analysis was conducted on data consolidated from three serial cross-sectional national surveys of women in Lebanon (2007, 2009 and 2012). A total of 6150 women were included in order to study the association between date of birth intervals and age at menarche. RESULTS: The mean age at menarche was 13.06 years, with a peak of the distribution at age 12. Women born before 1950 had a significantly higher mean age at menarche (13.21) compared to those born in 1970 and thereafter (12.95). A stratified analysis showed that women living outside the metropolitan Greater Beirut (GB) area were characterized by an older mean age at menarche (13.11) in all date of birth intervals compared to those in GB (12.89). However, age at menarche declined more significantly over the last two decades among women outside GB, compared to those living in GB. CONCLUSIONS: Epidemiological figures emerging from this study confirm that trends in Lebanon are in line with a global pattern of decreasing age at menarche. Urban-rural differences suggest that higher caloric content of diet and consequent early overweight, more evident in urban areas, are likely determinants of younger menarche. Evidence from this study calls for an urgent implementation of comprehensive multisectoral obesity prevention in children in Lebanon.

Impact of Age at Menarche on Breast Cancer: The Assessment of Recall Bias.

BACKGROUND: Our aim was to determine the association between age at menarche (AAM) and breast cancer adjusted for recall bias (misclassification) in AAM. METHODS: We have used data provided from a case-control study conducted in Iran from 2005 to 2009. The cases and controls were frequency matched based on 5-year age groups and region of residence. First, logistic regression was conducted to estimate the odds ratio (OR) and second, Bayesian analysis was applied to estimate the ORs adjusted for misclassification. RESULTS: The study was conducted on 880 cases and 998 controls. In the assumption of no correction for recall bias on self-reported AAM, the OR was 1.36 (95% Credible Interval (0.98, 1.90). Based on a sensitivity value = 71% and a specificity value = 81% (the indices about the ratio of true recall of AAM) for the case and control groups (as the first scenario), the AAM ≤ 12 years of age was associated with a lower OR for breast cancer by 1.23 (95% Credible Interval: 0.50, 3.13). In the other scenario, with consideration of 100% sensitivity and specificity of self- reported AAM in the case group, and 71% and 81% sensitivity and specificity of the item in the control group, the related OR between breast cancer and AAM was found increased to 2.96 (95% Credible Interval: 0.75, 7.66). CONCLUSION: After adjustment for misclassification related to recall bias, this study provides evidence that the self-reported mode of AAM has a moderate impact on calculation of the OR.

The biological standard of living in Indonesia during the 20th century: Evidence from the age at menarche.

This article analyses long-term changes in the mean age at menarche (MAM) as a biological indicator of changes in the standard of living in Indonesia. It finds that MAM was about 15.5 for birth cohorts in the late-19th century, decreasing to 14.5 by the 1930s, at which level it stagnated until the gradual decrease resumed since the early 1960s to around 12.5 in the mid-2000s. The article considers that long-term improvements in nutrition, educational attainment and health care explain these trends. An international comparison of long-term changes finds that MAM in Indonesia was much lower than in Korea and China until respectively 1970 and 1990, but comparable to Japan until 1950 and to Malaysia until 1930. The article presents reasons why these differences are unlikely to be related to dissimilarities in climate and ethnicity, and concludes that they are indicative of relative standards of living.

Age at maturation, body structure and their relationship with socioeconomic factors.

Introduction: In this study, we aimed to identify the differences in body structure between early, average, and late maturing girls, taking into account family characteristics assessing socio-economic and living conditions. Methods: This study was conducted in the years 2003 and 2013 in Warsaw, Poland and comprised 788 girls in the age group of 11-19 years. The data were collected using a questionnaire which included parental education and profession, girls' date of birth, age at menarche, and lifestyle characteristics. The measurements included height; weight; skinfolds on arm, under scapula, and on abdomen; arm circumference; and body mass index (BMI). The girls were divided into three groups: early, average, and late maturing. To eliminate the age differences, for each of the examined somatic variable, a "z" score was calculated. We analysed the combined data of both years (2003 and 2013) due to the lack of difference in the mean age at menarche. The primary objective of this study was to assess the relationship between somatic body structure and socioeconomic and lifestyle factors among early, average, and late maturing girls. Results: Early maturing girls possessed higher body weight and BMI. In families with only one child, the age at menarche was found to be the earliest than in families with more than one child. Body weight, BMI, arm circumference, and fatfold thickness was found to be reduced in case of girls whose parents had better education and profession than their peers. Higher levels of stress were associated with higher body mass, greater BMI, arm circumference, and skinfolds in early maturing girls. The associations between body structure with physical activity and family was mainly correlated with body weight and BMI. Conclusion: Socioeconomic and lifestyle factors may be helpful in some levelling of differences in the body structure between girls differing in the age at menarche, especially the level of stress and the education and profession of parents.

Factors associated with early age at menarche among Thai adolescents in Bangkok: A cross-sectional study.

BACKGROUND: The age at menarche in the Thai population has not been determined since 1997. This study recruited adolescents in Bangkok Metropolis to determine the age at menarche and its associations with health and socioeconomic status. METHODS: This cross-sectional study used a two-step stratified sampling strategy to recruit 1,020 female students, aged 10-16 years, from schools in Dusit district, Bangkok, Thailand. Self-reported data on age at menarche and social determinants of health were collected from participants and their parents. A trained research nurse collected anthropometric data. RESULTS: Mean age at menarche was 11.8 ± 1.0 years, and age at menarche was significantly correlated with year of birth (r = -0.4, p < 0.001). Students from schools that are part of Bangkok Metropolis had the lowest mean age at menarche. Participants born in 2000-2003 having their first period at < 11.8 years numbered 5.5 times (95% CI: 3.80-8.18) and 5.0 times (95% CI: 3.6-8.0) greater than those born in 1997-1999 by univariate and multivariate analysis, respectively. Year of birth significantly associated with age at menarche in univariate and multivariate analysis (p = 0.001). CONCLUSION: The mean age at menarche among female adolescents in Bangkok Metropolis was occurring earlier and was inversely associated with year of birth in this cohort. Only year of birth were associated with age at menarche in the multivariate regression models to adjust for potential confounders.

Puberty Experiences of Low-Income Girls in the United States: A Systematic Review of Qualitative Literature From 2000 to 2014.

PURPOSE: Puberty is a critical period of development that lays the foundation for future sexual and reproductive health. It is essential to learn about the puberty experiences of low-income girls in the United States given their increased vulnerability to negative sexual and reproductive health outcomes. To understand the present-day puberty experiences of this population, we conducted a qualitative systematic review. METHODS: We systematically searched the peer-reviewed literature published between 2000 and 2014 on the puberty experiences of low-income girls in the United States. Reviewers screened titles, abstracts, and the full texts of articles. Using standardized templates, reviewers assessed the methodologic quality and extracted data. Data were synthesized using thematic analysis. Confidence in each finding was assessed using Confidence in the Evidence from Reviews of Qualitative research. RESULTS: Twenty qualitative articles were included. They described the experiences of mostly African-American, Caucasian, and Hispanic girls living primarily in urban areas of Northeastern United States. Five overarching themes emerged: content of girls' puberty experiences, quality of girls' puberty experiences, messages girls receive about puberty, other factors that shape girls' puberty experiences, and relationships that shape girls' experiences of puberty. CONCLUSIONS: The limited existing evidence suggests that low-income girls in the United States are unprepared for puberty and have largely negative experiences of this transition.

Biological standards of living: age at menarche vs height.

Background Researchers typically use height to understand the growth environment, but recent evidence suggests that height does not reflect it well; height can even be misleading. Aim This study compared age at menarche and height to assess which better reflected the growth environment. Subjects and methods This study employed the Indonesian Family Life Survey to extract information on age at menarche from 7831 women and height from 7946 men, both aged 15-49 and born in 1944-1983. It drew on GDP per capita in childhood to represent the growth environment. The means of the two anthropometrics by birth decade were calculated. The trends in the two were then compared and each was regressed on the growth environment and a time trend. Results Between 1944-1953 and 1974-1983, the mean age at menarche decreased from 14.5 to 13.9, while height increased from 160.9 cm to 162.6 cm. Despite the expected broad trends, age at menarche was more closely related to the growth environment than height in graphs, correlation coefficients and regression results. Conclusion The results recommend using more than one anthropometric to investigate changes in the biological standards of living.

Improvement in the biological standard of living in 20th century Korea: Evidence from age at menarche.

OBJECTIVES: We used age at menarche to understand improvement in the biological standard of living in South Korea during the 20th century. METHODS: The main dataset, the Korean National Health and Nutrition Examination Survey, provided a consistent source of nationally representative data with a large number of observations over a long period of time. We calculated mean ages at menarche by birth year and estimated the rate of decrease in age at menarche, while avoiding survival bias. RESULTS: The mean age at menarche decreased from 16.64 for the birth year 1941 to 12.68 for the birth year 1992, decreasing 0.78 (or 0.81 in a regression) years per decade for the period. Comparisons with other populations demonstrate that this is the fastest rate of decline ever known. In contrast to other developed countries, the decreasing rate in Korea does not appear to slow. We also compared the trend in age at menarche to that of height and found that the rate of increase in height is also the fastest in history. CONCLUSIONS: Age at menarche is an appropriate index of change in the general standard of living in South Korea over the 20th century. Am. J. Hum. Biol. 29:e22882, 2017. © 2016 Wiley Periodicals, Inc.

Correlation of body mass index levels with menarche in adolescent girls in Shaanxi, China: a cross sectional study.

BACKGROUND: Menarche is a milestone for adolescent girls. The timing of menarche is influenced by genetics, social status and nutritional status (e.g., height, weight and body mass index [BMI]) and impacts future health (e.g., obesity and breast cancer). There have been many studies on trends in age at menarche among adolescent girls in China, but few have investigated associations between growth status and the timing of menarche. This study examined the association between age at menarche and growth status among adolescent girls in Western China. METHODS: The participants in this cross sectional study came from three geographical regions of Shaanxi Province. A total of 533 adolescent girls from urban and rural areas were randomly selected. Trained investigators administered a standard questionnaire to each participant during a face-to-face interview and carried out anthropometric measurements. RESULTS: The average age at menarche was 13.3 years. There were statistically significant differences in BMI z-scores between pre-menarcheal and post-menarcheal girls of the same age and these differences were related to socioeconomic factors. Girls who had reached menarche, in particular those aged 13-14 years, were significantly taller (P < 0.01) and had higher BMI (P < 0.01) than girls in the same age group who had not reached menarche. CONCLUSIONS: BMI is associated with the timing of menarche but socioeconomic factors are also important.

The influence of climate on age at menarche: Augmented with the influence of ancestry.

Samples representative of South Korea, Indonesia, and Peninsular Malaysia were analyzed and the influence of climate on age at menarche was investigated. The sample size was 24,651 for Korea (birth years 1941-1992), for Indonesia 8331 (birth years 1944-1988) plus 20,519 (birth years 1978-1997), and 2842 for Peninsular Malaysia (birth years 1927-1968). Respondents recalled their age at menarche. The mean age at menarche was calculated for each birth year by country, and for Malaysia, additionally by ancestry. It has been found that mean ages at menarche for the early birth years were much younger in Indonesia than in Korea despite similar levels of socioeconomic conditions (proxied by GDP per capita). For example, for the birth year 1944, the mean age at menarche was 14.45 years for Indonesia and 16.19 years for Korea-a difference of 1.74 years. It was necessary to double the Korean GDP per capita to make the Korean mean age at menarche the same as the Indonesian one. Chinese and Malay women in Peninsular Malaysia were further analyzed, and the results provided indirect evidence that the difference between Korea and Indonesia was not due to ancestry differences. Results in multivariate settings provided consistent results. It has been concluded that climate exerts a significant influence on age at menarche because the relatively easy availability of food in the tropics increases energy intake while the absence of cold weather decreases energy expenditure on maintenance and activity.

Age at Menarche and Factors that Influence It: A Study among Female University Students in Tamale, Northern Ghana.

INTRODUCTION: Age at menarche reflects the health status of a population. This marks the beginning of sexual maturation and is affected by nutritional status and prevailing environmental conditions. This study measured the menarcheal age of female undergraduate students in northern Ghana and explored factors that could impact on the onset of menarche. METHOD: GraphPad 5.01 was used to analyze data collected from 293 randomly selected female university students in a cross-sectional study using a semi-structured questionnaire. Association between different variables was tested using appropriate statistical tests. RESULTS: The mean recall age at menarche of participants in this study was 13.66 ±1.87 years for a female population of mean age, 23.04±5.07 years. Compared to female students who lived in rural settings, urban and suburban areas dwellers significantly recorded earlier menarche (p = 0.0006). Again, females from high income earning families experienced menarche earlier than those who were born to or lived with lower income earners (p = 0.003). Lower menarcheal age increased risk of experiencing menstrual pain prior to menses rather than during menstrual flow for dysmenorrhic females. (13.52±2.052 vrs 13.63±1.582 year; χ2 = 7.181, df = 2, p = 0.028). CONCLUSION: Mean menarcheal age of female university students in northern Ghana was 13.66 years. Females from urban areas and high income families had earlier menarche. Compared to the very first Ghanaian study reported in 1989, the menarcheal age decline was 0.11 year per decade.

Biosocial correlates of age at menarche in a British cohort.

BACKGROUND: A large number of biosocial variables have been shown to associate with age at menarche, but the results are inconsistent and differentiate not only between countries but within countries as well. AIM: This study examined age at menarche in a British national cohort in relation to 21 biosocial and anthropometric variables. SUBJECTS AND METHODS: The analyses were based on 4483 girls from the British National Child Development Study (NCDS). RESULTS: The majority of girls reached menarche between 12-14 years of age. Girls from smaller families, those living in the East and South East, South West, West Midlands and Wales regions, in tied housing and uncrowded conditions, not sharing a bedroom, not having free school meals, whose families lived in households without financial problems had started menstruating earlier than their peers from families with lower socioeconomic status. However, when all the significant variables were analysed together significant associations remained only for mother's age at menarche, height and weight at 7 years, family size and tenure. CONCLUSIONS: The results of this study support the hypotheses that intra-uterine growth and conditions in early life as well as socio-economic background are associated with the timing of menarche and that greater childhood growth and better SES are related to earlier menarche.

Sexual stature dimorphism as an indicator of living standards?

BACKGROUND: A group of researchers has argued that sexual stature dimorphism (SSD) can serve as an indicator of living standards. This argument is based on evidence that boys' physical growth is more sensitive to environmental conditions than girls' physical growth. Because Korea's economic growth in the second half of the 20th century was unprecedentedly rapid, according to their logic, it is likely to see an increasing trend in SSD. AIM: We aimed to determine whether SSD can serve as an accurate indicator of living standards for a population that would exhibit a pronounced trend in SSD, providing that the logic for use of SSD is correct. SUBJECTS AND METHODS: We employed nationally representative Korean men born in 1941-1990 (n = 17 268) and women born in 1941-1991 (n = 22 543) and estimated mean heights by sex and birth years. We then calculated SSD values and charted the trend. RESULTS: Although male height increased faster than female height, the SSD trend was flat for the pooled observations and for sub-groups by socioeconomic status. CONCLUSION: These results cast doubt on the argument for using SSD as an indicator of living standards.

Association Assessment among Risk Factors and Breast Cancer in a Low Income Country: Bangladesh.

BACKGROUND: In the low incoming country Bangladesh, breast cancer is second most common neoplasm and is increasing at an alarming rate among females. Lack of awareness and illiteracy are contributory factors for late presentation and therefore mortality. PURPOSE: To examine associations of different factors with breast cancer mortality and to raise awareness among the women of society in Bangladesh. MATERIALS AND METHODS: This descriptive case-control study was conducted on 160 participants from April 2011 till July 2014. Through a valid questionnaire covering personal and family history, data were collected by face to face interview. For analyzing correlations among factors with breast cancer data, binary logistic regression, Pearson's χ2- value, odd ratios and p-value tests were conducted with SPSS version 20. RESULTS: The mean age of the patients was 43.0 (SD= ± 11.12). In ascending order the leading significant factors were hormone therapy (p<0.0000, OR=4.897), abortion (p<0.0001, OR=3.452), early start menarche (p<0.0002, OR=3.500), family history (p<0.0022, OR=3.235), and late menopause (p<0.0093, OR=3.674) with both χ2 test and logistic regression analyses. Non-significant factors were cancer experience, fatty food habits, marital status and taking alcohol. CONCLUSIONS: Regarding the investigation of this study, significant and insignificant factor's correlation visualization with breast cancer will be helpful to increase awareness among Bangladeshi women as well as all over the world.

Biological maturation of youth athletes: assessment and implications.

The search for talent is pervasive in youth sports. Selection/exclusion in many sports follows a maturity-related gradient largely during the interval of puberty and growth spurt. As such, there is emphasis on methods for assessing maturation. Commonly used methods for assessing status (skeletal age, secondary sex characteristics) and estimating timing (ages at peak height velocity (PHV) and menarche) in youth athletes and two relatively recent anthropometric (non-invasive) methods (status-percentage of predicted near adult height attained at observation, timing-predicted maturity offset/age at PHV) are described and evaluated. The latter methods need further validation with athletes. Currently available data on the maturity status and timing of youth athletes are subsequently summarised. Selection for sport and potential maturity-related correlates are then discussed in the context of talent development and associated models. Talent development from novice to elite is superimposed on a constantly changing base-the processes of physical growth, biological maturation and behavioural development, which occur simultaneously and interact with each other. The processes which are highly individualised also interact with the demands of a sport per se and with involved adults (coaches, trainers, administrators, parents/guardians).