Trends in age at menarche and adult height in selected African countries (1950-1980)

Estimated timing of the first menstrual period and dietary and nutritional correlates of menarche among urban school-going adolescents in four sub-Saharan African sites

Characterizing the timing of menarche and the factors that are associated with it is important for understanding a population's reproductive health needs and long-term health trajectories. We estimated the age at the menstrual onset among adolescent girls and the association between dietary and nutritional factors and menarche in four sub-Saharan African urban sites. We used cross-sectional school-based data from 2307 female adolescents aged 10-14 years collected by the Africa Research, Implementation Science, and Education (ARISE) Network in Ouagadougou, Burkina Faso; Addis Ababa, Ethiopia; Khartoum, Sudan; and Dar es Salaam, Tanzania. Logit models were used to estimate the median age at menarche at each site. Associations between menarche and BMI-for-age, stunting, dietary quality and food insecurity across settings were assessed using Poisson regression models adjusted for country and school levels. The estimated median age at menarche was 13.1 years (95% confidence interval: 12.7, 13.5) in Ouagadougou; 12.9 (12.6, 13.2) in Addis Ababa; 13.3 (12.7, 13.6) in Khartoum; and 13.2 (12.3, 14.0) in Dar es Salaam. Between 18% and 49% of the girls in each setting had already menstruated. Based on the pooled multivariable models, underweight participants were 42% less likely (adjusted prevalence ratio [PR] 0.58 [0.44, 0.77]) to have experienced menarche in comparison to normal-weight individuals. The likelihood of experiencing menarche increased for overweight [PR 1.47 (1.30,1.66)] and obese [PR 1.57 (1.35,1.82)] in comparison to normal-weight girls. Those stunted were 47% less likely to have experienced menarche [PR 0.53 (0.41, 0.69)] than their nonstunted counterparts. A lower likelihood of menarche among those experiencing moderate/severe hunger when compared to those with no/little hunger was also observed (PR 0.78 [0.63,0.96]). No evidence of association with dietary quality was found. Further research is needed to strengthen the body of evidence and inform evidence-based initiatives in low- and middle-income settings.

Pattern of linear growth and progression of bone maturation for girls with early-onset puberty: A mixed longitudinal study

Background and objective

With a worldwide trend to earlier age of onset of puberty, the prevalence of early-onset puberty (EP) among girls has increased. The impact of EP on the pattern of linear growth and bone maturation is unclear. Accordingly, the objective of our study was to describe this pattern for girls with EP in Shenzhen, China.

Methods

A total of 498 untreated girls diagnosed with EP at Shenzhen Children's Hospital, China, between January 2016 and December 2021. A total of 1,307 anthropometric measurements and 1,307 left-hand radiographs were available for analysis. Artificial intelligence (AI) was used to determine bone age (BA). Participants were classified into groups according to chronological age (CA) and BA. The pattern of linear growth (height) and progression of bone maturation was described between groups using the Lambda-Mu-Sigma (LMS) method. Published height-for-CA and height-for-BA norm references for a healthy Chinese population were used for age-appropriate comparisons.

Results

The mean CA of appearance of first pubertal signs (breast buds) was 8.1 ± 0.5 years. Compared to norm-referenced data, girls with EP were significantly taller at a CA of 7-10 years. This was followed by a slowing in linear growth after a CA of 10 years, with 71 girls with EP having already achieved their target adult height. From 7 to 10 years of BA, the linear growth was slower in the EP group compared to norm-reference values. This was followed by a period of catch-up growth at 11.2 years of BA, with growth curves approaching norm-referenced values. The BA progressed rapidly from 7 to 8 years of age in about half of the girls with EP (median ΔBA/ΔCA >1.9), slowing, thereafter, until the period of catch-up growth at 11.2 years of BA.

Conclusions

BA provides a more reliable reference than CA to assess growth parameters among girls with EP. Our limited data set does indicate that EP does not negatively impact final adult height. Therefore, the growth curves from our study are relevant, providing a reference for pediatricians in this clinical population and, thus, preventing over-treatment for EP.

Is height related to fertility? An evaluation of women from low- and middle-income countries

OBJECTIVES

To present an empirical description of the association between height and lifetime fertility in women from low- and middle-income countries, allowing for flexible functional relationships.

METHODS

A pooled sample (N = 846 257) of women ages 35-49 in Demographic and Health Surveys (DHS) from 64 countries, with regional samples for Latin America, South Asia, and sub-Saharan Africa. Flexibly-estimated structured additive regression models estimate variations in the height-fertility relationship over the height distribution.

RESULTS

Across samples, height is shown to have nonlinear relationships with number of children ever born and age at first birth. Number of children increases with height until a maximum below average height, after which the number of children decreases. Age at first marriage decreases with height until a minimum below average height, and then increases. Except at the shortest heights, much of the variation in fertility is suggested to reflect socioeconomic differences across heights. At the shortest heights, variation is suggested to reflect later ages at first birth, except for women in sub-Saharan Africa.

CONCLUSION

A nonlinear relationship is indicated between height and fertility. Much of the relationship is suggested to reflect height-variations in socioeconomic status and age at first birth.

Heritability of Age at Menarche in Nigerian Adolescent Twins

Heritability of age at menarche (AAM) in African populations remains largely unknown. A question on AAM was given to 1803 [454 monozygotic (MZ), 823 same-sex dizygotic (DZ), and 526 female members of opposite sex] adolescent twins attending public schools in Lagos State, Nigeria. The age range of the sample was 12-18 years, with a mean (SD) of 14.57 (±1.70) years. The data included 905 missing cases consisting of those who had not experienced menarche and did not recall AAM. Missing values were imputed using the Expectation-Maximization algorithm. Kaplan-Meier analysis based on the imputed data yielded 13.23 years [95% CI [13.18, 13.28] for the mean and 13.00 years [95% CI [12.96, 13.04] for the median of AAM. Twin correlation and model-fitting analyses were performed on the basis of those who reported AAM (MZ = 82 complete pairs and 38 cotwin missing cases; DZ = 157 complete pairs and 99 cotwin missing cases). Maximum likelihood MZ and DZ twin correlations for AAM were .63 (95% CI [.48, .74]) and .33 (95% CI [.19, .45]) respectively. Model-fitting analyses indicated that 58% (95% CI [46, 67]) of the variance of AAM was associated with additive genetic influences with the remaining variance, 42% (33-54) being due to nonshared environmental influences including measurement error. The heritability estimate found in this study was within the range of those found in Asian and Western twin samples.

It is time to work on the extension of body growth and reproductive stages

There are three major changes for the human lifespan in the past half decade: the decreased age of sexual maturity, slight increase in age of menopause/ andropause, and a trend of increase in life expectancy. The ages of puberty and menopause are the transitions in life stages, such that early puberty leads to loss and late menopause leads to gain the lifespan. So far, the strategies for increased lifespan have been largely focused on the post-reproductive stage. These approaches are challenging and may at some point reach a plateau. It might be interesting to expand this focus to potentially delaying the puberty and extending the period of body growth, which might yield longer reproductive stages as well as the longer and healthier lifespan.

Secular trends of age at menarche and the effect of famine exposure on age at menarche in rural Chinese women

BACKGROUND

Over the past few decades, more studies have suggested that the age at menarche (AAM) has continued to decline. However, the AAM for women in resource-constrained areas is not clear. Moreover, the association between the China famine and AAM is still unclear in rural regions.

AIM

The study aimed to investigate the secular trends of AAM for women born between 1935 and 2000 and to further explore the effect of famine on AAM in rural China.

SUBJECTS AND METHODS

The study included 23444 women participants from the baseline study of Henan Rural Cohort study. Changing AAM over time was analysed using linear regressions. Multinomial logistic regression was conducted to analyse the association between famine exposure and AAM subgroups.

RESULTS

The age-standardized mean AAM was 14.74 years. The average AAM declined from 16.98 years for those born in 1935 to 13.87 years for those born in 2000, a decline of 0.077 years per 1 year and 0.729 years per decade. Compared to the reference group, women exposed to famine during fetal, early childhood, middle childhood, and late childhood were 1.376 (95% CI, 1.071 - 1.769), 1.848(95% CI, 1.512 - 2.259), 2.084(95% CI, 1.725 - 2.518), and 2.146 (95% CI, 1.788 - 2.576) times more likely to be ≥18 years of AAM than unexposed famine women, respectively.

CONCLUSION

AAM showed a decreasing trend in rural China. Furthermore, both fetal and childhood famine exposure, especially in late childhood, were positively associated with increased AAM compared to unexposed famine.

A secular trend in age at menarche in Yunnan Province, China: a multiethnic population study of 1,275,000 women

Background

Age at menarche (AAM) has shown different trends in women from different ethnic and economic regions in recent decades. Data on AAM among multiethnic women living in developing areas are scarce.

Methods

Data on AAM from 1,275,000 women among 26 ethnicities in Yunnan Province, China, who were born from 1965 to 2001 were obtained from the National Free Preconception Health Examination Project from 2010 to 2018. The patterns of AAM trends were analysed according to ethnic group, area of residence, and socioeconomic status.

Results

The mean AAM was 13.7 ± 1.21 years (95% CI 13.697–13.701), with a decrease from 14.12 (±1.41) among women born before 1970 to 13.3 (±1.04) among those born after 2000. The decline was 0.36 years per 10-year birth cohort, and the plateau has not yet been reached in Yunnan. A secular trend of earlier AAM was observed in all 26 ethnic groups. The fastest rate of decline was observed for the Bai ethnicity (0.36 years per decade). Consistent declining trends in AAM appeared among extreme-, middling-, and nonpoverty economic patterns from 1965 to 2001, with reductions of 1.19, 1.44, and 1.5 years, respectively (P < 0.001). The peak reduction among middling poverty and extreme poverty occurred in the early 2000s (0.4 and 0.32 years). Multivariate analysis showed a significant difference in the declining trends in AAM along rural/urban lines (P < 0.001).

Conclusion

There was a secular trend towards a younger AAM during the twentieth century and early twenty-first century birth cohorts in the Yunnan population. Considering the difference in AAM trends due to ethnic and socioeconomic status in Yunnan, the health authority should utilize flexible adjusted health care strategies in different regions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11951-x.

Secular Trends in Height, Body Mass and Mean Menarche Age in Romanian Children and Adolescents, 1936-2016

Secular trends in anthropometric parameters have been documented in most European countries, but no data is available regarding Romanian. The aim of the study was to calculate secular trend in height, body mass and mean menarche age for Romanian children and adolescents.

METHODS

A secondary data analysis was performed using ten data sets for urban and eight data sets for rural boys and girls, age 5-15 years, covering 80 years (1936 to 2016). Secular trend in height (cm/decade), body mass(kg/decade) and mean menarche age (years) were calculated.

RESULTS

Overall, there was a positive secular trend for height in both genders, which parallels the gross domestic product (GDP)/capita difference, more pronounced in boys, across all age-groups, with a maximum for 15 years-old boys (~3 cm/decade) and 13 years-old girls (~2 cm/decade). Body mass trend was also positive, more accentuated in the rural population. Mean age at menarche was higher in rural compared to urban girls, had a negative trend with the disappearance of the difference in the latest available data set (2013).

CONCLUSION

In summary, an overall positive and ongoing secular trend in height and body mass was documented in Romanian children and adolescents, especially for the pubertal age-range, in concordance to other western countries, but out of phase by approximately 20 years.

Timing and determinants of age at menarche in low-income and middle-income countries

INTRODUCTION

Understanding the timing and determinants of age at menarche is key to determining potential linkages between onset of puberty and health outcomes from a life-course perspective. Yet, we have little information in low-income and middle-income countries (LMICs) mainly due to lack of data. The aim of this study was to analyse trends in the timing and the determinants of menarche in LMICs.

METHODS

Using 16 World Fertility Survey and 28 Demographic and Health Surveys (DHS) from 27 countries, we analysed cohort trends and used fixed-effects models for DHS surveys to investigate sociodemographic and regional effects in the timing of age at menarche.

RESULTS

Trends of the mean age at menarche across time within and between countries show a declining or stalling path. Results of the determinant modelling show the relationship with wealth changes over time although not consistently across countries. We see a shift from poorer women having earlier menarche in earlier surveys to richer women having earlier menarche in later surveys in Indonesia, the Philippines and Yemen, while in Egypt, the reverse pattern is evident.

CONCLUSIONS

There is a considerable gap in both literature and data on menarche. We see a trend which is declining rapidly (from 14.66 to 12.86 years for the 1932 and 2002 cohorts, respectively), possibly at a faster pace than high-income countries and with a strong link to socioeconomic status. This study calls for menarche questions to be included in more nationally representative surveys and greater use of existing data because of its impact on life-course health in fast-ageing settings. Further studies will need to investigate further the use of the age at menarche as an indicator of global health.

Age at menarche in Nigerian demographic surveys

Age at menarche was investigated using data collected from demographic surveys (WFS, DHS) conducted in Nigeria between 1982 and 2018, all of which were based on large representative samples of the female population. Linear-logistic regressions were used to estimate mean age at menarche, its trends and its risk factors. Mean age at menarche had underwent a marked secular decline from 15.02 years for girls born in 1933 to 13.78 years for girls born in 2003. In multivariate analysis, height (stature), body mass index (BMI), level of education and household wealth had independent effects on age at menarche, whereas urban residence had no effect. Socioeconomic gradients were large: +9 years of schooling was associated with a -0.52 year decrease in age at menarche, and +2 standard deviations in household wealth with a -0.33 year decrease. The impact of anthropometry was even greater: +2 standard deviations in height was associated with a -0.99 year decrease in age at menarche, and +2 standard deviations in BMI with a -1.42 year decrease. Northern provinces had a higher mean age at menarche than southern provinces. Compared with independent sources, long-term trends in age at menarche, as well as their fluctuations, appeared to be correlated with trends and fluctuations in income per capita and in under-five mortality, but not with divergent trends in adult height.

How can two biological variables have opposing secular trends, yet be positively related? A demonstration using timing of puberty and adult height

Timing of puberty and adult height have opposing secular trends yet are positively associated in individuals. We demonstrate this using data from a single sample and discuss possible statistical and epidemiological reasons behind it. The sample comprised 365 females from Fels Longitudinal Study born 1929-1992. We used Super-Imposition by Translation and Rotation (SITAR) to estimate individual age at peak height velocity (PHV) and PHV from serial height data (8149 observations between 5 and 24 years). General linear regression was used to investigate the association between height and age at PHV, and secular trends in height, age at PHV and PHV. Although adult height increased 0.42 (95% CI: 0.08, 0.77) cm per decade, and age at PHV decreased 1.14 (-3.74, 1.45) weeks per decade, adult height increased by 2.44 (1.78, 3.10) cm per year higher age at PHV. We found tentative evidence of the positive association between age at PHV and adult height strengthened 0.25 (-0.09, 0.59) cm each decade. Secular trends in related variables may differ if the between-individual and between-cohort associations are different. To understand if a secular trend in one variable has contributed to a trend in another, each needs to be modelled over time, together with the changing association between them.