Height, marriage, and partner characteristics for women in low- and middle-income countries.

In both historical and contemporary populations, taller individuals have been shown to fare better in marriage markets. Height has been positively associated with the propensity to marry, length of marriage, and the education and economic outcomes of marriage partners. These associations are most commonly identified for male samples. Studies using female samples are few in number and mixed in their findings. This study uses a pooled sample of national surveys from 64 countries to evaluate how women's height may relate to the timing of marriage and partner characteristics. The findings suggest that women's height shows modest associations to the timing of marriage, partner education, and partner occupation status. The strongest effects from height occur toward the extremes of the height distribution. There is some variation in these relationships across three major developing regions (Latin America, Sub-Saharan Africa, and South Asia), and for education in particular, the association is shown to be stronger in countries with shorter average female height.

Height, BMI, and relative economic standing in children from developing countries.

OBJECTIVES: The purpose of this study was to estimate a height-BMI association in child and female adolescent populations in developing countries, and to evaluate the potential role of relative economic status in this association. METHODS: Flexible structured additive regression models were used to estimate associations between height, BMI, and relative wealth. Linear regression models were used to evaluate height-wealth interactions on BMI outcomes. The models were applied to pooled samples of 971,180 children under 5 years of age and 225,718 adolescent females between 15 and 19 years. Samples were taken from Demographic and Health Surveys from 64 developing countries. RESULTS: Children exhibited a strong inverse association between height and BMI over the entire distribution of height. Female adolescents showed a weak inverse association. Relative economic status was associated with a stronger height-BMI relationship in early-life (<3 years) and a weaker relationship as children age into their fifth year. CONCLUSIONS: Relative economic status may protect against consequences of a negative height-BMI association in young children in developing countries, first by promoting higher body weight among shorter children during the risk period for early-life mortality, and afterwards by limiting body weight in shorter children when overweight and obesity become longer-term health issues.

A Longitudinal Study of Income Differences in the Height-BMI Relation among U.S. Children Ages 6 to 14.

Previous work has shown a positive height-obesity association in U.S. children that is more pronounced in those from lower-income families than in those from higher-income families. That work has been limited to cross-sectional analysis. This study evaluates income differentials in the inter-temporal associations between childhood height and obesity in U.S. children ages 6 to 14. Pooled samples of 9,670 female and 10,110 male children from the U.S. Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K) were evaluated in multilevel mixed effects models. The results indicated a modest height-income interaction such that the concurrent height-obesity association was weaker at higher incomes. This strengthened into adolescence for females and weakened for males. With respect to height growth, for lower-income males, being shorter before the typical start of the growth spurt (≈ 9 years) and experiencing faster later growth (between 11 and 14 years) were attributes less strongly associated with subsequent obesity. There were no indicated income interactions with height growth in females.

Income gradients in oral health according to child age.

This study aimed to confirm whether the well-known income disparities in oral health seen over the life course are indeed absent in 9- to 11-yr-old children, and to explore the role of access to dental care in explaining the age-profile of the income gradient in child oral health. We used data from the 2007 United States National Survey of Children's Health. Income gradients in parental reports of children's decayed teeth or cavities, toothache, broken teeth, bleeding gums, and fair/poor condition of teeth were assessed in stratified analyses according to age of child (1-5, 6-8, 9-11, 12-14, and 15-17 yr), using survey logistic regression to control for family-, parental-, and child-level covariates. Health insurance status and use of preventive dental care were the indicators for children's access to dental care. The adjusted ORs for the effect of family income on having decayed teeth or cavities, toothache, and fair/poor condition of teeth were not significant in 9- to 11-yr-old children. Different age-patterns were found for broken teeth and bleeding gums. The attenuation of the income gradients in having decayed teeth or cavities, toothache, and fair/poor condition of teeth, previously seen in 9- to 11-yr-old children, was also seen in 15- to 17-, 12- to 14-, and 6- to 8-yr-old children, respectively, after controlling for children's access to dental care. This study supports the attenuation of income inequalities in oral health in 9- to 11-yr-old children. Access to dental care could attenuate income gradients in oral health in other age groups.

OVERWEIGHT/OBESITY AND HUMAN CAPITAL FORMATION FROM INFANCY TO ADOLESCENCE: EVIDENCE FROM TWO LARGE US COHORTS.

Body mass index (BMI) levels in US children and adolescents have increased over the past several decades. The negative health effects of this trend are well-documented. Recent work has evaluated the potential effects on skills formation. Studies are mixed on whether there is an association between high BMI and skills outcomes, and those that estimate causal effects find none. This paper offers estimates on the causal effect of BMI-defined overweight and obesity on skills formation using two large cohorts of contemporary US children followed from infancy to 5 years and from kindergarten (6 years) to the eighth grade (14 years). Significant negative associations were observed in the random effects models for males in early life with respect to a mental skills assessment, for females during the pre-school years for reading and maths assessments, for both males and females during the schooling years for reading assessments and for females during the schooling years for maths assessments. Fixed effects models yielded a significant negative association only with respect to the latter. The implication of these findings is that any improvement in skills outcomes that may accompany reductions in obesity prevalence may depend on whether interventions are general to overall health productivity or whether they are specific to dietary and exercise behaviours.

Associations between household income, height and BMI in contemporary US children: infancy through early childhood.

BACKGROUND: Previous studies report positive associations between household income and height in childhood and negative associations between income and body mass index (BMI). No study has evaluated concurrent associations in early-life. AIM: To evaluate the association between household income and anthropometric development in early-life. SUBJECTS AND METHODS: The Early Childhood Longitudinal Study-Birth Cohort (ECLS-B) is a representative sample of US children born in 2001 and followed from ~9 months through 5 years. A generalized linear mixed modelling framework estimates income associations to the levels and velocities of height and BMI. RESULTS: A doubling of permanent income is associated with an ~0.26 cm height advantage over the ages of the sample and an approximate 0.11 cm/year faster velocity at 9 months. All race-sex sub-groups show some positive association between income and height. Income shows little association to BMI at 9 months but by 5 years a doubling of income is associated with a 0.25 kg/m(2) lower BMI. This is suggested to derive from a lower BMI velocity associated with higher income. The BMI relationships are generally reflective of white and Hispanic children. CONCLUSION: The findings suggest that associations between income and anthropometric development in US children have origins in early-life.

Flexible nonlinear estimates of the association between height and mental ability in early life.

OBJECTIVES: To estimate associations between early-life mental ability and height/height-growth in contemporary US children. METHODS: Structured additive regression models are used to flexibly estimate the associations between height and mental ability at approximately 24 months of age. The sample is taken from the Early Childhood Longitudinal Study-Birth Cohort, a national study whose target population was children born in the US during 2001. RESULTS: A nonlinear association is indicated between height and mental ability at approximately 24 months of age. There is an increasing association between height and mental ability below the mean value of height, but a flat association thereafter. Annualized growth shows the same nonlinear association to ability when controlling for baseline length at 9 months. CONCLUSIONS: Restricted growth at lower values of the height distribution is associated with lower measured mental ability in contemporary US children during the first years of life.

Physical growth and cognitive skills in early-life: evidence from a nationally representative US birth cohort.

This paper establishes associations between length/height and cognitive skills in infancy, toddlerhood, and school-entry. The data come from the Early Childhood Longitudinal Study--Birth Cohort (ECLS-B), a representative longitudinal sample of US children born in 2001. A positive association between length/height and cognition is found as early as 9 months and continues through school-entry. These associations are robust to controls for birthweight and economic status. Early growth is also shown to be a stronger predictor of reading and math skills in kindergarten than attained height. Girls exhibit stronger evidence of this latter result than boys. These findings have implications for the interpretation of early life as a critical period for the growth-cognition relationship.

Associations between household income, height, and BMI in contemporary US schoolchildren.

This paper evaluates the association between income and physical development in a nationally representative sample of contemporary US schoolchildren followed from kindergarten to eighth grade (average ages of 6-14). A generalized linear mixed modeling framework is used to evaluate height and body mass index (BMI) as both levels and annualized growth in a pooled sample. Contemporary US schoolchildren show income variation in height that is significant but modest at around .1cm (in kindergarten) to .4cm (eighth grade) increases per doubling of income. An exception is found for Hispanic children who show faster height velocity associated with higher income through childhood yielding a 1.0cm increase per doubling of income by the eighth grade. All groups except black males show a negative relationship between income and BMI that becomes stronger with age with an average .8kg/m(2) lower BMI per doubling of income by the eighth grade. These results are robust to the inclusion of baseline anthropometric controls. The analysis suggests that higher-income US schoolchildren enter mid-adolescence as taller but with lower proportional body mass relative to their lower-income counterparts.

Trends in the associations between family income, height and body mass index in US children and adolescents: 1971-1980 and 1999-2008.

AIM: This paper evaluates trends in the childhood and adolescent associations between family income, height and body mass index (BMI) between the periods 1971-1980 and 1999-2008. SUBJECTS AND METHODS: US-born children (aged 2-11) and adolescents (aged 12-19) in the NHANES I, NHANES II and 1999-2008 NHANES are evaluated for BMI and height using flexibly-estimated structured additive regression models. RESULTS: Three trends are identified: BMI gains have been greater in lower-income relative to higher-income children and adolescents; height has increased more in lower-income relative to higher-income children (but not in adolescents); and BMI has increased more in taller children than shorter children (but not in adolescents). Following from these trends is that contemporary children exhibit a negative height-income interaction effect on BMI such that the inverse association between income and BMI is larger in taller children. Similar results hold when categorical obesity is considered but with modest height-related changes and income-height interaction effect in adolescents. Race-sex differences are explored and descriptive evidence on the potential role of changes in caloric intake is presented. CONCLUSION: The relationship between the economic environment and growth in US youth has changed in recent decades. Contemporary taller and lower-income children exhibit greater body mass and obesity.

Socioeconomic status, height, and obesity in children.

The substantial increase in the prevalence of child obesity over recent decades and its association with a number of negative health and economic outcomes suggests its strong potential as an influence on the lifecourse development of health and productivity. This paper evaluates interactive effects between family socioeconomic status (SES) and height on child obesity in the United States. Using the 1999-2006 National Health and Nutrition Examination Surveys (NHANES), the results of this paper confirm previous findings that taller children exhibit greater propensity towards obesity as measured by body mass index (BMI) and that obesity is inversely related to family SES as measured by poverty status. The analysis adds to the existing literature by showing that the magnitude of the SES-obesity association is larger in taller children. Age and sex patterns are evaluated that suggest the SES-height interaction persists through childhood and adolescence in males but is only evident in females during adolescence. Interaction effects are also shown to be most evident in white males and Hispanic females. Policy implications are discussed and directions for future work are suggested.

Male-female differences in the association between socioeconomic status and atherosclerotic risk in adolescents.

Recent work suggests that the association between socioeconomic status and coronary heart disease may be stronger in adult women than in men. This paper evaluates a parallel to these findings in adolescence (aged 12-17) by examining male-female differences in the association between family income and markers of atherosclerosis in the 1999-2004 US National Health and Nutrition Examination Surveys. We found that moving from the 25th to 75th income percentile is associated with up to a 5.4% greater reduction in the probability of low HDL-C in females compared to males, and a 4.5% greater reduction in the probability of high C-reactive protein. No associations are found between income and LDL-C in either sex. A stronger income-adiposity association in females explains part of the C-reactive protein result, but not the HDL-C result. The implications of these findings are discussed in the context of lifecourse development of coronary heart disease and related health policy.

An evaluation of the age-profile in the relationship between household income and the health of children in the United States.

Previous work has shown that the income gradient in child health for the United States becomes steeper with age. This paper shows a similar pattern using the 1996-2005 Medical Expenditure Panel Surveys (MEPS). A framework is also presented to evaluate cumulative and contemporaneous income effects through the use of baseline health controls. The analysis shows that poor health is more persistent in older children, and that the income gradient is substantially flattened over age groups when controlling for baseline health. However, even when controlling for baseline health, there remains a stronger effect from income on the health of adolescents. These results may reflect a cumulative effect from income that explains much of the strengthening association between income and health before adolescence, with a remaining stronger contemporaneous association in that age group. The analysis is unable to identify a major role of chronic conditions or injuries in these relationships.

Gender differences in the management of risk factors for cardiovascular disease: the importance of insurance status.

Despite cardiovascular disease (CVD) being the leading killer of both sexes in the US, there are indications that men and women have different experiences in the health system with prevention and treatment practices. Beyond largely descriptive findings, little research exists that addresses how men and women may differ in their response to certain key influences on CVD health services utilization. This paper examines gender differentials in the effect of insurance coverage on CVD preventive health services in the US. An economics framework is used to model individual demand for preventive services as a function of insurance status, while controlling for a comprehensive set of explanatory variables. The services analyzed include cholesterol and blood pressure screening, pharmaceutical use for hypertension and lipid disorders, and CVD-related physician visits. Both general and high-risk samples are evaluated. The results show that while a lack of insurance is associated with lower rates of utilization in both men and women, there are no observed gender differences in insurance-effects for recommended intervals of risk factor screening in the general population. However, for individuals with previously diagnosed heart disease or stroke, a lack of coverage is more strongly associated with lower rates of screening, pharmaceutical management, and physician contact in women than men. Potential reasons for these findings are discussed and policy implications are noted.