Is age at menarche a good predictor of future body fat? The case of a developing country

The association between early menarche and higher-risk cardiometabolic profile: a dose-response analysis of the Tabari cohort at enrollment phase

Objectives

The association between age at menarche and higher-risk cardiometabolic factors is controversial and more strands of evidence are required. Therefore, in this study, we aimed to investigate the effect of early menarche on cardiometabolic profile in a large-scale cohort population.

Study design

Data collected in the enrollment phase of the Tabari cohort study were utilized for the present study. We analyzed data from 6,103 women aged 35-70 years. Logistic regression and dose-response (trend) analyses were used to investigate the effect of early menarche on prevalence of diabetes, dyslipidemia, obesity, high waist circumference (WC), high waist-to-hip ratio (WHR), and high waist-to-height ratio (WHtR).

Results

The results of the adjusted logistic regression analysis showed that women who experienced early menarche had significantly higher odds of obesity (odds ratio: 1.64, 95% CI: 1.36-1.99, P for trend <0.001), high WC (odds ratio: 1.34, 95% CI: 1.07-1.67, P for trend = 0.035), high WHR (odds ratio: 1.32, 95% CI: 1.05-1.66, P for trend = 0.057), and high WHtR (odds ratio: 1.83, 95% CI: 1.22-2.74, P for trend = 0.006) compared to those aged ≥14 at menarche. The prevalence of dyslipidemia was also higher among women who experienced early menarche than in women aged ≥14 at menarche (79.9% vs. 76.6%), but the difference was not statistically significant (P = 0.098). Additionally, each year of earlier menarche was significantly associated with an increase in the chance of diabetes (by 5%), obesity (10%), high WC (5%), and high WHtR (13%).

Conclusion

The present study showed that early menarche is a strong predictor for later development of obesity and diabetes, and for high WC, WHR, and WHtR. Among all factors examined, age at menarche had the greatest predictive power for WHtR. As an age-dependent anthropometric index for central obesity, WHtR is more suitable as an index for identification of individuals with increased cardiometabolic risk.

Having more siblings delays menarche in Indonesia

OBJECTIVES

Tanner (1968, Scientific American, 218(1), 21-27) concluded that having more siblings delayed menarche, but many subsequent studies have reported diverging results. We thus aimed to investigate whether the initial conclusion remains valid by controlling for sibship size and birth order together, analyzing a large number of observations, drawing on a nationally representative sample, adjusting for childhood socioeconomic status, and considering a developing country. We additionally aimed to assess the importance of sibling sex for age at menarche.

METHODS

We analyzed 10 212 ever-married women aged 20+ in the last wave of the Indonesian Family Life Survey. We regressed age at menarche on sibship size, birth spacing, and childhood socioeconomic status. We subsequently divided sibship size into the numbers of brothers and sisters.

RESULTS

Having more siblings was related to later menarche, and the relationship was strengthened when the birth order was controlled for. In addition, those born earlier experienced menarche later. Sibling sex was irrelevant to age at menarche, boosting the importance of sibship size itself.

CONCLUSIONS

Our results support the earlier conclusion that having more siblings delays menarche.

The Null Relation between Father Absence and Earlier Menarche

Researchers have claimed that the absence of a biological father accelerates the daughter's menarche. This claim was assessed by employing a large and nationally representative sample of Indonesian women. We analyzed 11,138 ever-married women aged 15+ in the Indonesian Family Life Survey 2015. We regressed age at menarche on the interaction of father absence (vs. presence) and mother absence (vs. presence) at age 12 with or without childhood covariates. For robustness checks, we performed a power analysis, re-ran the same specification for various subgroups, and varied the independent variable of interest. All results produced a null relation between father absence and age at menarche. The power analysis suggests that a false negative was unlikely. Our review of the literature indicates that the claim of the relation between father absence and earlier menarche was based on weak statistical foundations. Other studies with higher-quality datasets tended to find no relation, and our results replicated this tendency. Therefore, the influence of father absence does not appear to be universal.

The Association between Height and Hypertension in Indonesia

There is growing interest in the influence of early-life conditions on the development of disease. Among diseases in adulthood, hypertension is particularly important for the developing world because considerably more people there are and will be afflicted with the disease than in the developed world and hypertensives there are often unaware of their disease status. We employed height as a proxy for the influence of early-life conditions and estimated the relation between height and hypertension status in Indonesia. We analysed 9,597 men and 10,143 women, aged 25-70. We employed a linear probability model to relate height to hypertension status by sex and age. When we controlled for an array of covariates, a 10cm increase in height was related to an approximately 7% point reduction in the likelihood of being hypertensive for both men and women. This is about a quarter of the prevalence of hypertension in Indonesia. This relation was linear and stronger among older individuals. In addition, the pre- and post-pubertal environments (measured by leg and trunk lengths, respectively) contributed similarly to hypertension. Further evidence suggests that women are more likely to be hypertensive at older ages because they are on average shorter than men.

The fatter are happier in Indonesia

PURPOSE

Although obesity and happiness are known to be negatively related in the developed world, little attention has been paid to this relationship in the developing world. We thus investigated the relationship in Indonesia and attempted to explain the underlying rationale.

METHODS

We considered about 12,000 respondents aged 15+ for each gender obtained from the Indonesian Family Life Survey 2007 by relating a measure of happiness to weight-related measures in ordered probit models.

RESULTS

The relationship between obesity and happiness was positive in Indonesia, and this relationship was robust. Our evidence suggests that the contrasting results for the two worlds result from affordability of obesity. That is, while even low socioeconomic status (SES) individuals in the developed world can afford to be obese, only high SES individuals in the developing world can do.

CONCLUSIONS

Our findings imply that obesity prevention in the developing world requires different measures than those used in the developed world.

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.

The effects of smoking on obesity: evidence from Indonesian panel data

Background

It has been known that smoking is negatively related to weight-related outcomes. However, it has been difficult to determine whether the relationship is causal, and if so, how strong it is. We attempted to estimate the approximately causal effects of smoking on weight, body mass index (BMI), and obesity.

Methods

The Indonesian Family Life Survey provided a sample of over 9000 men aged 15–55 years—each of them was observed in 1993, 1997, 2000 and 2007. The preferred method was a fixed effects model; that is, we related changes in smoking status or smoking intensity to changes in weight-related outcomes, while controlling for time-varying covariates. We also compared these results to those estimated by ordinary least squares and assessed the importance of controlling for time invariant individual heterogeneity.

Results

Although the effects of smoking were precisely estimated in a statistical sense, their size was minuscule: a quitter would gain weight by at most 1 kg, or a smoker would lose weight by the same amount. The results were similar for BMI and obesity. When we did not control for time invariant individual heterogeneity, the size of the relationship was overestimated at least three times.

Conclusions

Smoking exerted little influence on weight, and it was important to control for bias stemming from time invariant individual heterogeneity.

Sick But Unaware: Hypertension in Indonesia

Discrepancies between self-reported and measured hypertension pose a great risk to health because they prevent timely treatment. Analyzing the Indonesian Family Life Survey, we compared self-reported and measured hypertension to assess the extent of the misclassification of hypertension. Building on this, we estimated factors related to self-reported and measured hypertension. Our results show that different factors were involved in each case, suggesting that they are two different phenomena. More importantly, we estimated factors that increased awareness of hypertension and found that visiting a health facility was a very effective way of increasing awareness of hypertension among hypertensive patients.