Smoking during pregnancy is associated with child overweight independent of maternal pre-pregnancy BMI and genetic predisposition to adiposity

Trends in childhood body mass index between 1936 and 2011 showed that underweight remained more common than obesity among 398 970 Danish school children

AIM

To examine trends in all body mass index (BMI) groups in children from 1936 to 2011.

METHODS

We included 197 694 girls and 201 276 boys from the Copenhagen School Health Records Register, born between 1930 and 1996, with longitudinal weight and height measurements (6-14 years). Using International Obesity Task Force criteria, BMI was classified as underweight, normal-weight, overweight and obesity. Sex- and age-specific prevalences were calculated.

RESULTS

From the 1930s, the prevalence of underweight was stable until a small increase occurred from 1950 to 1970s, and thereafter it declined into the early 2000s. Using 7-year-olds as an example, underweight changed from 10% to 7% in girls and from 9% to 6% in boys during the study period. The prevalence of overweight plateaued from 1950 to 1970s and then steeply increased from 1970s onwards and in 1990-2000s 15% girls and 11% boys at 7 years had overweight. The prevalence of obesity particularly increased from 1980s onwards and in 1990-2000s 5% girls and 4% boys at 7 years had obesity. These trends slightly differed by age.

CONCLUSION

Among Danish schoolchildren, the prevalence of underweight was greater than overweight until the 1980s and greater than obesity throughout the period. Thus, monitoring the prevalence of childhood underweight remains an important public health issue.

Appetitive traits from childhood to adolescence: Analysis of their stability, derivation of trajectory profiles, and associated characteristics

This study aimed to assess the potential stability of appetitive traits from childhood to early adolescence, identify groups of individuals with distinct trajectories for these traits, and explore their association with other child and family characteristics. Participants were 5040 children from the Generation XXI cohort. Appetitive traits were assessed with the Children's Eating Behaviour Questionnaire (CEBQ) at ages seven, 10, and 13 (eight subscales). Mixed-effect models estimated individual trajectories of appetitive traits and Gaussian mixture models identified groups following different trajectories (appetitive trait trajectory profiles). Appetitive traits showed moderate-to-high stability across the three ages (intra-class correlation coefficients:0.66-0.83); most of the variance observed across time were due to persistent individual differences rather than age-related changes. Six appetitive trait trajectory profiles were identified: 'Moderate appetite' (scores close to the average) (29% of children), 'Small to moderate appetite' (lowest food approach and emotional eating) (26%), 'Increasing appetite' (increasing food approach) (15%), 'Avid appetite' (highest food approach and lowest food avoidance) (12%), 'Smallest appetite' (highest food avoidance and low food approach) (10%), and 'Small appetite but increasing' (decreasing high food avoidance and Desire to Drink) (8%). In multinomial logistic regression, these profiles were associated with different child and family characteristics. Compared to children with a 'Moderate appetite' profile, those with higher BMI, who desired a thinner body, whose mothers were younger, had lower education, higher pre-pregnancy BMI (OR = 1.07; 95%CI:1.04,1.09), smoked during pregnancy (OR = 1.51; 95%CI:1.21,1.90), and used more restrictive feeding practices (OR = 1.79; 95%CI:1.57,2.03) had increased odds of belonging to the 'Avid Appetite'. In conclusion, distinct appetitive trait trajectory profiles emerged, differentiating individuals with avid and small appetites. These findings have implications for identifying children at higher risk for obesogenic profiles.

Overweight or obesity in children born after assisted reproductive technologies in Denmark: A population-based cohort study

BACKGROUND

The association between assisted reproductive technologies (ARTs) and the body mass index (BMI) of children remains controversial. Confounding by morbidity and other factors associated with parental infertility may have biased studies comparing children born after ART with children born after no treatment. We investigated the associations between different fertility treatments and BMI in children at age 5 to 8 years, adjusting for and stratifying by causes of parental infertility.

METHODS AND FINDINGS

This Danish cohort study included 327,301 children born between 2007 and 2012 (51% males, median age at follow-up 7 years). Of these, 13,675 were born after ART, 7,728 were born after ovulation induction with or without intrauterine insemination [OI/IUI], and 305,898 were born after no fertility treatments. Using the International Obesity Task Force (IOTF) standards, we defined overweight (BMI ≥ IOTF-25) and obesity (BMI ≥ IOTF-30). We compared children born after ART versus OI/IUI; intracytoplasmic sperm injection (ICSI) versus conventional in vitro fertilization (IVF); and frozen-thawed versus fresh embryo transfer and estimated crude and adjusted prevalences of children with overweight or obesity at age 5 to 8 years, prevalence odds ratios (PORs), and differences in mean BMI z-scores. Adjustment was performed using stabilized inverse probability of treatment weights, including parity, year of conception, parental causes of infertility, age, educational level, comorbidities, maternal country of origin, BMI, and smoking as covariates. The crude prevalence of obesity was 1.9% in children born after ART, 2.0% in those born after OI/IUI, and 2.7% in those born after no fertility treatment. After adjustment, children born after ART and OI/IUI had the same prevalence of being overweight (11%; POR 1.00, 95% confidence interval [CI] 0.91 to 1.11; p = 0.95) or obese (1.9%; POR 1.01, 95% CI 0.79 to 1.29; p = 0.94). Comparison of ICSI with conventional IVF yielded similar pattern (POR 0.95, 95% CI 0.83 to 1.07; p = 0.39 for overweight and POR 1.16, 95% CI 0.84 to 1.61; p = 0.36 for obesity). Obesity was more prevalent after frozen-thawed (2.7%) than fresh embryo transfer (1.8%) (POR 1.54, 95% CI 1.09 to 2.17; p = 0.01). The associations between fertility treatments and BMI were only modestly different in subgroups defined by the cause of infertility. Study limitations include potential residual confounding, restriction to live births, and lack of detailed technical information about the IVF procedures.

CONCLUSIONS

We found no association with BMI at age 5 to 8 years when comparing ART versus OI/IUI or when comparing ICSI versus conventional IVF. However, use of frozen-thawed embryo transfer was associated with a 1.5-fold increased risk of obesity compared to fresh embryo transfer. Despite an elevated relative risk, the absolute risk difference was low.

Analysis of the Influence of Pre-Pregnancy BMI and Weight Gain during Pregnancy on the Weight of Healthy Children during the First 2 Years of Life: A Prospective Study

Background: Increased pre-pregnancy maternal BMI (pBMI) and gestational weight gain (GWG) have been found to increase infants’ birthweight and result in the programming of child weight and impact its later weight gain. Aim: To assess the impact of pBMI and GWG on the weight of children from birth to 2 years of age and over the duration of breastfeeding. Methods: Single Centre observational prospective longitudinal cohort study. Data were collected from medical records, and medical history. The analysis of multiple linear and mixed models was involved. Findings: 20% of females were overweight, while 13% were obese before the pregnancy. An overall model, including gender and smoking, indicated a significant impact of pBMI category on a child’s birth mass (p = 0.01). The GWG category affected a child’s birth weight (p = 0.018, Effect size 0.41). pBMI did not affect the breastfeeding duration. Conclusion: pBMI and GWG correlate with birth weight and weight in neonatal period, however they become insignificant in later childhood. Weight assessment methods among children aged up to two years of age require standardization. Maternal weight before the pregnancy nor the weight gain during the pregnancy do not influence the length of breastfeeding. The biggest limitation was the small sample size and the failure to account for weight gain per trimester of pregnancy. Further research on a larger population should be continued.

Developmental origins of disease highlight the immediate need for expanded access to comprehensive prenatal care

The prenatal environment plays a critical role in shaping fetal development and ultimately the long-term health of the child. Here, we present data linking prenatal health, via maternal nutrition, comorbidities in pregnancy (e.g., diabetes, hypertension), and infectious and inflammatory exposures, to lifelong health through the developmental origins of disease framework. It is well-established that poor maternal health puts a child at risk for adverse outcomes in the first 1,000 days of life, yet the full health impact of the in utero environment is not confined to this narrow window. The developmental origins of disease framework identifies cognitive, neuropsychiatric, metabolic and cardiovascular disorders, and chronic diseases in childhood and adulthood that have their genesis in prenatal life. This perspective highlights the enormous public health implications for millions of pregnancies where maternal care, and therefore maternal health and fetal health, is lacking. Despite near universal agreement that access to antenatal care is a priority to protect the health of women and children in the first 1,000 days of life, insufficient progress has been achieved. Instead, in some regions there has been a political shift toward deprioritizing maternal health, which will further negatively impact the health and safety of pregnant people and their children across the lifespan. In this article we argue that the lifelong health impact attributed to the perinatal environment justifies policies aimed at improving access to comprehensive antenatal care globally.