Camila Corvalán

Preconceptional and maternal obesity: epidemiology and health consequences.

Obesity in women of reproductive age is increasing in prevelance worldwide. Obesity reduces fertility and increases time taken to conceive, and obesity-related comorbidities (such as type 2 diabetes and chronic hypertension) heighten the risk of adverse outcomes for mother and child if the woman becomes pregnant. Pregnant women who are obese are more likely to have early pregnancy loss, and have increased risk of congenital fetal malformations, delivery of large for gestational age infants, shoulder dystocia, spontaneous and medically indicated premature birth, and stillbirth. Late pregnancy complications include gestational diabetes and pre-eclampsia, both of which are associated with long-term morbidities post partum. Women with obesity can also experience difficulties during labour and delivery, and are more at risk of post-partum haemorrhage. Long-term health risks are associated with weight retention after delivery, and inherent complications for the next pregnancy. The wellbeing of the next generation is also compromised. All these health issues could be avoided by prevention of obesity among women of reproductive age, which should be viewed as a global public health priority. For women who are already obese, renewed efforts should be made towards improved management during pregnancy, especially of blood glucose, and increased attention to post-partum weight management. Effective interventions, tailored to ethnicity and culture, are needed at each of these stages to improve the health of women and their children in the context of the global obesity epidemic.

Nutrition, child growth, and chronic disease prevention

Countries undergoing the nutrition transition are experiencing a progressive increase in obesity and nutrition‐related chronic diseases (NRCDs). In transitional countries, stunting (shortness for age) and micronutrient deficiencies (iron, vitamin A, and zinc) in children coexist with obesity and NRCDs originating the double burden of nutritional disease. The causal web for obesity and NRCDs is complex and multifaceted; changes in diet and physical activity of the population are likely the main concurrent determinant factors. However, recent evidence suggests that specific patterns of prenatal and postnatal growth are also potential contributors. Evidence indicates that intervention strategies to prevent malnutrition should emphasize improvements in linear growth in the first 2–3 years of life rather than aim at gaining weight. Avoiding excessive weight gain relative to height gain (BMI) is especially relevant after the first 2 years of life. Routine assessment of child growth based on the new World Health Organization (WHO) standard, defining energy needs based on the recent Food and Agricultural Organization (FAO)/WHO norms, and providing critical micronutrients to support lean mass growth are critical to prevent obesity and NRCDs starting early in the life course. These actions should contribute in the prevention and control of obesity in childhood and thus help prevent NRCDs in future generations of adults.

How can the Developmental Origins of Health and Disease (DOHaD) hypothesis contribute to improving health in developing countries

The relevance of nutrition during pregnancy and early infancy in defining short-term health and survival has been well established. However, the Developmental Origins of Health and Disease (DOHaD) paradigm provides a framework to assess the effect of early nutrition and growth on long-term health. This body of literature shows that early nutrition has significant consequences on later health and well-being. In this article, we briefly present the main consequences of malnutrition that affect human growth and development and consider how the DOHaD paradigm, with its evolutionary implications, might contribute to better addressing the challenge of improving nutrition. We examine how this paradigm is particularly appropriate in understanding the health and nutrition transition in countries that face the double burden of nutrition-related diseases (acute malnutrition coexisting with obesity and other chronic diseases). We focus on stunting (low height-for-age) to examine the short- as well as long-term consequences of early malnutrition with a life-course, transgenerational, and multidisciplinary perspective. We present current global and regional prevalence of stunting and discuss the need to reposition maternal and infant nutrition not only in health and nutrition intervention programs but also in consideration of the emerging research questions that should be resolved to better orient program and policy decisions.

Structural responses to the obesity and non-communicable diseases epidemic: the Chilean Law of Food Labeling and Advertising

In 12 July 2012, the Chilean Senate approved the Law of Food Labeling and Advertising, resulting from the joint efforts of a group of health professionals, researchers and legislators who proposed a regulatory framework in support of healthy diets and active living. Its goal was to curb the ongoing epidemic increase of obesity and non‐communicable diseases. Two actions included: (i) improving point of food purchase consumer information by incorporating easy‐to‐understand front‐of‐packages labeling and specific messages addressing critical nutrients, and (ii) decreasing childrens exposure to unhealthy foods by restricting marketing, advertising and sales. We summarize the work related to the laws release and discuss the conclusions reached by the various expert committees that were convened by the Ministry of Health to guide the development of the regulatory norms. Throughout the process, the food industry has overtly expressed its disagreement with the regulatory effort. The final content of the regulatory norms is still pending; however there are suggestions that its implementation will be delayed and might be modified based on the industry lobbying actions. These lessons should contribute to show the need of anticipating and addressing potential barriers to obesity‐prevention policy implementation, particularly with respect to the role of the private sector.

Obesity indicators and cardiometabolic status in 4-y-old children

BACKGROUND In adults and adolescents, obesity is positively associated with cardiovascular disease risk factors; however, evidence in preschool children is scarce. OBJECTIVE The objective was to assess the relations between obesity indicators and cardiometabolic risk factors in 324 Chilean children 4 y of age. DESIGN We collected anthropometric measurements and calculated general indicators of obesity [weight, body mass index (BMI), sum of 4 skinfold thicknesses, percentage fat, and body fat index] and central obesity (waist circumference, waist-to-hip ratio, waist-to-height ratio, and truncal fatness based on skinfold thickness). We measured blood sample concentrations of C-reactive protein, interleukin-6, homeostasis model assessment of insulin resistance, triglycerides, and total, LDL, and HDL cholesterol. We used correlation and multiple linear regression analyses. RESULTS The prevalence of obesity (BMI-for-age z score >2, World Health Organization 2006), central obesity (> or = 90th percentile, third National Health and Nutrition Examination Survey), and lipid disorders was high (13%, 11%, and > or = 20%, respectively), and 70% of the children had at least one cardiometabolic risk factor. Most correlations between obesity and central obesity indicators were moderate to strong (0.40 < r < 0.96). Obesity was positively but weakly associated with C-reactive protein in both sexes and with homeostasis model assessment of insulin resistance only in girls (all r < 0.3, P < 0.05). Obesity indicators were unrelated to interleukin-6 and lipid concentrations (P > 0.05). Overall, obesity indicators explained, at most, 8% of the variability in cardiometabolic risk factors. CONCLUSIONS Obesity and central obesity were common, and most of the children had at least one cardiometabolic risk factor, particularly lipid disorders. Obesity and central obesity indicators were highly intercorrelated and, overall, were weakly related to cardiometabolic status. At this age, body mass index and waist circumference were poor predictors of cardiometabolic status.

Accelerated growth in early life and obesity in preschool Chilean children.

In Chile, childhood obesity rates are high. The purpose of this article is to compare BMI growth characteristics of normal (N), overweight (OW), and obese (OB) 5‐year olds from 0 to 5 years and explore the influence of some prenatal factors on these patterns of growth. The study was done on a retrospective cohort of 1,089 5‐year olds with birth weight >2,500 g. Weight and height were obtained from records at nine occasions (0–36 months); at 52 and 60 months, we measured them. At 60 months, children were classified as N, OW, and OB. At each age, BMI and z‐score of BMI (BMI Z) differences were compared among groups. The influence of birth weight, pre‐pregnancy BMI, and prenatal variables (weight gain, smoking, and presence of diabetes and preeclampsia) on BMI Z differences between N and OB was also explored. Adiposity rebound (AR) was not observed for the N, although for the OW, it occurred ∼52 months and for the OB at ∼24 months. BMI Z differences between N and OB were significant from birth, but were greatest between 6–12 and 36–52 months. Additional adjustment by birth weight, pre‐pregnancy BMI, and prenatal variables decreased the BMI Z differences for the first 24 months with virtually no effect after this age. Accelerated growth in OB children from post‐transition countries occurs immediately after birth, much earlier than the AR. The influence of prenatal factors on adiposity acquisition may extend at most until 2 years of life, although BMI gains thereafter are more related to postnatal variables.

Obesity is positively associated with dehydroepiandrosterone sulfate concentrations at 7 y in Chilean children of normal birth weight

Background: In low-birth-weight girls, obesity increases the risk of premature adrenarche and metabolic complications. However, the consistency of this association in normal-birth-weight children and its potential mediators remain unknown. Objectives: The objectives were to assess the associations between obesity indicators and dehydroepiandrosterone sulfate (DHEAS) at 7 y of age and to evaluate the role of hormonal markers on these associations. Design: We assessed in 969 participants (6.9 y; 48% girls; all Tanner I) in the Growth and Obesity Chilean Cohort Study the associations between DHEAS and weight, BMI, waist circumference (WC), waist-to-height ratio, skinfold thickness, and percentage total fat (bioimpedance) and determined whether these associations were related to insulin, insulin-like growth factor I (IGF-I), and leptin. We also compared BMI and height growth from 0 to 7 y of age in nonobese and obese children with normal and high DHEAS (≥75th percentile) at 7 y. Results: DHEAS concentrations were similar between girls (30.3 ±1.86 μg/dL) and boys (29.4 ±1.73 μg/dL) (P > 0.05); 17.3% of children were obese (BMI-for-age z score ≥2 SD). Adiposity indicators were positively and similarly associated with DHEAS [ie, BMI, β standardized regression coefficient: 0.23 (95% CI: 0.17, 0.29); WC, β standardized regression coefficient: 0.23 (95% CI: 0.16, 0.30)]; these associations were only partially related to IGF-I and leptin. Obese children had twice the risk of high DHEAS (OR: 2.16; 95% CI: 1.51, 3.09); at 7 y, obese children with high DHEAS were fatter and more centrally obese than their counterparts (P < 0.05), although their previous growth was similar (P > 0.05). None of the results differed by sex (P > 0.05). Conclusion: In children of normal birth weight, obesity is positively associated with DHEAS at 7 y of age.

Impact of growth patterns and early diet on obesity and cardiovascular risk factors in young children from developing countries

Non-communicable chronic diseases are now a worldwide epidemic. Diet and physical activity throughout life are among its main determinants. In countries undergoing the early stages of the nutrition transition weight gain from birth to 2 years of life is related to lean mass gain, while ponderal gain after age 2 years is related to adiposity and later diabetes and CVD risk. Evidence from developing countries undergoing the more advanced stages of the nutrition transition is limited. The early growth patterns of a cohort of Chilean children born in 2002 with normal birth weight who at 4 years had a high prevalence of obesity and CVD risk factors have been assessed. Results indicate that BMI gain in early life, particularly from 6 months to 24 months, is positively associated with adiposity and CVD risk status at 4 years. These results together with existing evidence suggest that actions to prevent obesity and nutrition-related chronic diseases in developing countries should start early in life, possibly after 6 months of age. This approach should consider assessing the effect of mode of feeding and the amount and type of energy fed, as well as the resulting growth patterns. The challenge for researchers addressing the nutrition transition is to define the optimal nutrition in early life, considering not only the short- and long-term health consequences but also taking into account the stage of the nutritional transition for the given population of interest. The latter will probably require redefining optimal postnatal growth based on the context of maternal size and fetal growth.

Tobacco use in pregnant women: analysis of data from Demographic and Health Surveys from 54 low-income and middle-income countries

BACKGROUND Worldwide, use of tobacco is viewed as an important threat to the health of pregnant women and their children. However, the extent of tobacco use in pregnant women in low-income and middle-income countries (LMICs) remains unclear. We assessed the magnitude of tobacco use in pregnant women in LMICs. METHODS We used data from Demographic and Health Surveys (DHS) done in 54 LMICs between Jan 1, 2001, and Dec 1, 2012, comprising 58 922 pregnant women (aged 15-49 years), which were grouped by WHO region. Prevalence of current tobacco use (smoked and smokeless) was estimated for every country. Pooled estimates by regions and overall were obtained from random-effects meta-analysis. FINDINGS Pooled prevalence of any tobacco use in pregnant women in LMICs was 2·6% (95% CI 1·8-3·6); the lowest prevalence was in the African region (2·0%, 1·2-2·9) and the highest was in the Southeast Asian region (5·1%, 1·3-10·9). The pooled prevalence of current tobacco smoking in pregnant women ranged from 0·6% (0·3-0·8) in the African region to 3·5% (1·5-12·1) in the Western Pacific region. The pooled prevalence of current smokeless tobacco use in pregnant women was lowest in the European region (0·1%, 0·0-0·3) and highest in the Southeast Asian region (2·6%, 0·0-7·6). INTERPRETATION Overall, tobacco use in pregnant women in LMICs was low; however high prevalence estimates were noted in some LMICs. Prevention and management of tobacco use and exposure to second-hand smoke in pregnancy is crucial to protect maternal and child health in LMICs. FUNDING None.

Effect of growth on cardiometabolic status at 4 y of age

BACKGROUND Cardiovascular disease (CVD) risks are increasingly being diagnosed in children and track into adulthood. Growth is associated with CVD risk in adulthood; however, its contribution to CVD risks in children facing the obesity epidemic is unclear. OBJECTIVE The objective was to assess relations between growth from age 0 to 4 y and CVD status at 4 y in 323 Chilean children with normal birth weight. DESIGN From health records we obtained weight and height every 6 mo from age 0 to 3 y and calculated body mass index (BMI; weight/height(2)). At age 4 y, we measured height, waist circumference, insulin, glucose, and plasma lipids; infant feeding information was provided by the mothers. Outcomes were metabolic score (waist-to-height ratio + glucose + insulin + triglycerides - HDL-cholesterol z scores/5), total cholesterol (TC):HDL cholesterol, and homeostasis model of assessment of insulin resistance. RESULTS At 4 y, the prevalence of obesity was 13%. Changes in BMI, particularly from 6 to 24 mo, predicted a higher metabolic score (standardized regression coefficient = 0.29; 95% CI: 0.16, 0.42) but were unrelated to homeostasis model of assessment of insulin resistance and TC:HDL cholesterol. Height changes were not associated with CVD risks at the age of 4 y. Mode of infant feeding was unrelated to CVD status at 4 y; however, in children who were exclusively breastfed at 4 mo, an increase in BMI from 0 to 6 mo was positively associated with TC:HDL cholesterol at 4 y (standardized regression coefficient = 0.24; 95% CI: -0.02, 0.50), whereas in children who were partially or nonbreastfed at 4 mo, it was negatively associated with TC:HDL cholesterol at 4 y (standardized regression coefficient = -0.30; 95% CI: -0.52, -0.08). CONCLUSION In children with normal birth weight and a high prevalence of obesity at 4 y, changes in BMI after 6 mo predicted a higher overall CVD risk at 4 y.