Is leg length a biomarker of early life conditions? Evidence from a historically short population

Secular changes in the waist, hips circumferences and selected associated indicators, among preschool children from Kraków (Poland), between 1983 and 2018

OBJECTIVES

Waist circumference and derived indicators are great for measuring the risk of abdominal obesity. The main aim of the study was to assess the changes in the waist, hips circumferences and selected associated indicators, among preschool children (3-7 years of age) from Kraków, Poland, between 1983, 2008 and 2018.

METHODS

The research was conducted in randomly selected kindergarten in Krakow (Poland). The 1983 cohort consisted of 1414 children and the 2008 and 2018 series included 1050 preschoolers each. Analyzed characteristics included waist and hip circumferences, body height, waist-to-hips ratio (WHR) and waist-to-height ratio (WHtR).

RESULTS

There was a negative secular trend regarding circumferences of the hips and waist, as well as WHtR. In girls, WHR was, the greatest in the 2018 cohort, while among boys there was a secular increase in the value of this parameter compared to the 2008 cohort, but not to the 1983 series.

CONCLUSIONS

The coexistence of currently noted trends with the previously described secular decrease in the prevalence of overweight/obesity and increase in trunk adiposity in the same population, suggests that WHR is preferable to body mass index in assessing the risk associated with excess adiposity in the population examined in the presented study.

Secular changes in limb lengths and proportions from 1952 to 2011 in children, adolescents, and young adults from Kolkata (India)

OBJECTIVES

The aim of the study was to investigate the intergenerational changes of upper and lower limb lengths as well as the values of the upper, lower limb, and intermembral indicators of children, adolescents, and young adults from Kolkata (India) between 1952 to 1966 and 2005 to 2011.

METHODS

The analysis was based on the results of anthropometric measurements of 7488 Bengali children, adolescents, and young adults. They were included in three cross-sectional surveys, carried out in 1955 to 1966, 1982 to 1983 (only males), and 2005 to 2011. The upper and lower limb lengths were obtained and the upper and lower limb indicators, as well as an intermembral index, were calculated. The differences between the cohorts were assessed using two-way ANOVA.

RESULTS

Positive, statistically significant, secular trends regarding the length of the lower and upper limbs as well as the value of the lower limb index were observed. Negative intergenerational changes were noted for the values of the upper limb indicator and intermembral index, suggesting that the secular increase of the length of the upper limbs was less pronounced than those of the body height and lower limbs length.

CONCLUSIONS

The secular increase regarding the lower limbs length was associated with the socioeconomic progress of the country, but the length of the upper limbs was less sensitive for those factors. It is also important to mention that there is still very little information on those characteristics in general, which further proves the need for similar studies.

The trend in the relationship of advanced maternal age to preterm birth and low birthweight

PURPOSE

As women in developed countries tend to delay childbearing, it becomes more important to understand the relationship of advanced maternal age to birth outcomes. We aimed to estimate the trend in the relationship of advanced maternal age to preterm birth and low birthweight.

MATERIALS AND METHODS

We analysed 4,264,417 ethnically homogeneous, singleton firstborns, born in hospitals to married couples in South Korea in 1997-2014. We regressed an indicator for preterm birth or low birthweight on advanced maternal age, the baby's sex, advanced paternal age, and a set of socioeconomic status (SES) variables by year. We then collected the coefficient on advanced maternal age and charted its trend. We repeated the same procedure for 4,153,313 second- and third births.

RESULTS

When we controlled for only the baby's sex, the relationship between advanced maternal age and preterm birth dramatically weakened in the 2000s and slightly more thereafter: being an older mother was related to a 3.5% point increase in preterm birth in the late 1990s, but this figure decreased to less than 2% points by the early 2010s. Controlling for advanced paternal age slightly decreased the relationship and controlling for SES hardly affected the relationship. We obtained almost the same results for low birthweight. Second- and third-borns exhibited a declining, much weaker influence of advanced maternal age on the birth outcomes.

CONCLUSIONS

In relative terms, mothers of advanced age were more likely to deliver preterm and low birthweight babies than younger mothers. In absolute terms, however, the risk was small in the 1990s and much smaller in the early 2010s.

Parents are rapidly getting older in South Korea

While scholars and policymakers have investigated the causes and consequences of low fertility, they have neglected a related issue: advanced parental age. This is an important issue because advanced parental age adversely affects babies in the short and long run. South Korea recently topped the list of low-fertility countries, and so this study examined the trends in parental age in this country. We analysed all births between 1997 and 2014, the census for 2000 and 2010, and aggregate marriage data to report the trends in age at first marriage, interval from marriage to first birth, and parental age at first birth and at all births. At every stage, age increased rapidly for both parents. As a result, of babies born to fathers aged 20-54, 20.2% were born to fathers aged 35-54 in 2000 with the proportion increasing to 38.7% in 2010 - almost double in a single decade. The corresponding figures for mothers increased from 6.7% to 17.2% - more than double. Potential parents and policymakers can use this information to time births more appropriately, thereby reducing risks to babies and mothers.

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.

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.

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.

Why did children grow so well at hard times? The ultimate importance of pathogen control during puberty

Background and objectives: Secular increase in human height and performance occurred in Europe throughout the 20th century despite the temporally worsening access to nutrients during and after World War II. This pattern is paradoxical under the assumption of the major impact of pre- and postnatal growth conditions for determination of adult size and human capital.

Methodology: We examined the anthropometric parameters of Estonian girls born between 1938 and 1953, and measured around the age of 17 (n = 1475). This period involved two opposite trends in the economic and epidemiological situation: increasing birth-time economic hardships during the war and particularly in the post-war period, and decreasing infant mortality (a proxy of disease burden) after 1947.

Results: Height of girls was negatively affected by the number of siblings and positively by parental socioeconomic position, but these effects were weaker than the secular trend. Leg length (an indicator of pre-pubertal growth conditions) was independent of age and birth date while all other traits, including measures of performance (cranial volume, lung capacity and handgrip strength) showed acceleration. The best predictor of size at age 17 was, in most cases, infant mortality in the year when the girls were aged 11.

Conclusions and implications: Reduction of disease burden during pubertal growth can override effects of resource shortage at birth. Our results also support the idea that increasing efficiency of pathogen control can contribute to the secular increase in cognitive abilities, i.e. the Flynn effect, and that epidemiological transition is the main driver of secular increase in human capital.

The value of male height in the marriage market

Analyzing the Indonesian Family Life Survey 2007, this paper estimates the value of relative height (relative to the spouse's height) in the marriage market of a developing country. The results indicate that the value of a 1cm reduction in the husband's height relative to his wife's height is about 3% of his earnings. 3% of the mean of yearly earnings amounts to Rp. 492,000 or US$54 in 2007. That value is reduced to 1% when earnings-generating attributes are controlled for. This difference of 2% points can be considered the value that women attach to their husbands' earnings-generating attributes; meanwhile, the remaining 1% suggests that there are still other attributes that women look for in male height.

Intergenerational changes in knee height among Maya mothers and their adult daughters from Merida, Mexico

OBJECTIVES

To analyze differences in knee height (KH) between adult Maya mothers and daughters in Merida City, Mexico, and determine if these differences are associated with their childhood socioeconomic conditions.

METHODS

From September 2011 to January 2014, we measured KH and collected data on childhood conditions (place of birth, type of drinking water, family size, and fathers' occupation) from a sample of 180 Maya mother-daughter dyads. Mean KH intergenerational difference was calculated and compared for each category of socioeconomic variables and a multiple regression model was used to assess the association between childhood conditions and KH difference.

RESULTS

A relative increase of 1.05 cm (SD = 2.3 cm) or 0.45 standard deviations (effect size of difference) was observed in KH between generations. Place of birth was significantly associated with KH. With three other variables statistically adjusted for, the intergenerational KH difference was 1.5 cm greater when mothers were born outside Merida but daughters were born in the city. Piped water consumption by mother-daughter dyads was associated with 1.5 cm of increase in KH difference compared with dyads who consumed well water (P = 0.058).

CONCLUSIONS

The relative increase in KH between mothers and daughters represents a portion of the expected change in growth in a group that has experienced few substantial improvements in their living conditions. Some improvements in childhood living conditions resulting from the intergenerational transition from rural to urban environments seem to be linked to a modest, but statistically significant intergenerational increase in KH among Maya women in Merida.

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.