Maternal smoking during pregnancy and offspring body mass index and overweight: a systematic review and meta-analysis.

The present study aimed to conduct a systematic review and meta-analysis to evaluate the evidence on the association of maternal smoking during pregnancy with offspring body composition in childhood, adolescence and adulthood. MEDLINE, Web of Science and LILACS databases were searched. Reference lists were also screened. We included original studies, conducted in humans, that assessed the association of maternal smoking during pregnancy with offspring body mass index (BMI) and overweight in childhood, adolescence and adulthood, published through May 1st, 2018. A meta-analysis was used to estimate pooled effect sizes. The systematic review included 64 studies, of which 37 evaluated the association of maternal smoking during pregnancy with overweight, 13 with BMI, and 14 evaluated both outcomes. Of these 64 studies, 95 measures of effect were extracted and included in the meta-analysis. We verified that the quality of evidence across studies regarding maternal smoking in pregnancy and overweight and BMI of offspring to be moderate and low, respectively. Most studies (44 studies) were classified as moderate risk bias. Heterogeneity among studies included was high and, in the random-effects pooled analysis, maternal smoking during pregnancy increased the odds of offspring overweight (OR: 1.43, 95%CI: 1.35; 1.52) and mean difference of BMI (ß: 0.31, 95%CI: 0.23; 0.39). In conclusion, offspring of mothers who smoked during pregnancy have higher odds of overweight and mean difference of BMI, and these associations persisted into adulthood.

Maternal smoking during pregnancy and offspring body mass index and overweight: a systematic review and meta-analysis / Tabagismo materno durante a gravidez e índice de massa corporal e excesso de peso entre os filhos: uma revisão sistemática e metanálise / Tabaquismo materno durante el embarazo e índice de masa corporal y sobrepeso en los hijos: una revisión sistemática y metaanálisis

Abstract: The present study aimed to conduct a systematic review and meta-analysis to evaluate the evidence on the association of maternal smoking during pregnancy with offspring body composition in childhood, adolescence and adulthood. MEDLINE, Web of Science and LILACS databases were searched. Reference lists were also screened. We included original studies, conducted in humans, that assessed the association of maternal smoking during pregnancy with offspring body mass index (BMI) and overweight in childhood, adolescence and adulthood, published through May 1st, 2018. A meta-analysis was used to estimate pooled effect sizes. The systematic review included 64 studies, of which 37 evaluated the association of maternal smoking during pregnancy with overweight, 13 with BMI, and 14 evaluated both outcomes. Of these 64 studies, 95 measures of effect were extracted and included in the meta-analysis. We verified that the quality of evidence across studies regarding maternal smoking in pregnancy and overweight and BMI of offspring to be moderate and low, respectively. Most studies (44 studies) were classified as moderate risk bias. Heterogeneity among studies included was high and, in the random-effects pooled analysis, maternal smoking during pregnancy increased the odds of offspring overweight (OR: 1.43, 95%CI: 1.35; 1.52) and mean difference of BMI (β: 0.31, 95%CI: 0.23; 0.39). In conclusion, offspring of mothers who smoked during pregnancy have higher odds of overweight and mean difference of BMI, and these associations persisted into adulthood.

Resumo: Este estudo teve como objetivo realizar uma revisão sistemática e metanálise para avaliar as evidências sobre a associação entre tabagismo materno durante a gravidez e composição corporal dos filhos na infância, adolescência e vida adulta. Foram realizadas buscas nas bases de dados MEDLINE, Web of Science e LILACS, além de listas de referências. Incluímos estudos originais em seres humanos que avaliaram a associação entre tabagismo materno durante a gravidez e índice de massa corporal (IMC) e excesso de peso dos filhos na infância, adolescência e vida adulta, publicados até 1º de maio de 2018. A metanálise foi usada para estimar os tamanhos dos efeitos agregados. A revisão sistemática incluiu 64 estudos, dos quais 37 avaliaram a associação entre tabagismo materno durante a gravidez e excesso de peso, 13 com IMC e 14 com ambos os desfechos. Desses 64 estudos, foram extraídas 95 medidas de efeito, incluídas na metanálise. Verificamos que a qualidade das evidências nos estudos sobre o tabagismo materno e excesso de peso e IMC dos filhos era moderada e baixa, respectivamente. A maioria dos estudos (44) foi classificada como risco de viés moderado. A heterogeneidade entre os estudos era alta, e na análise de efeitos aleatórios agrupada, o tabagismo materno durante a gravidez aumentou a probabilidade de excesso de peso nos filhos (OR: 1,43; IC95%: 1,35; 1,52) e a diferença média do IMC (β: 0,31; IC95%: 0,23; 0,39). Conclui-se que filhos de mulheres que fumaram durante a gravidez têm maior probabilidade para excesso de peso e maior diferença média de IMC, e que essas associações persistem na vida adulta.

Resumen: El objetivo del presente estudio fue llevar a cabo una revisión sistemática y metaanálisis para evaluar la evidencia de asociación del tabaquismo materno durante el embarazo con el índice de masa corporal de los hijos durante la infancia, adolescencia y etapa adulta. Se buscó información en las siguientes bases de datos: MEDLINE, Web of Science y LILACS. También se analizaron listas de referencia. Se incluyeron estudios originales, realizados con humanos, que evaluaron la asociación del tabaquismo materno durante el embarazo con el índice de masa corporal (IMC) en los hijos, así como el sobrepeso en la infancia, adolescencia y etapa adulta, publicado el 1 de mayo de 2018. Se realizó un metaanálisis para estimar el tamaño de los efectos combinados. La revisión sistemática incluyó 64 estudios, donde 37 evaluaron la asociación del tabaquismo materno durante el embarazo con el sobrepeso, 13 con el IMC, y 14 evaluaron ambos resultados. De estos 64 estudios, se obtuvieron 95 medidas de efecto que se incluyeron en el metaanálisis. Verificamos que la calidad de las evidencias en los diferentes estudios, respecto tabaquismo materno durante el embarazo y el sobrepeso, así como el IMC en los hijos, era moderada y baja, respectivamente. La mayor parte de los estudios (44 estudios) estaba clasificada como de riesgo moderado de sesgo. La heterogeneidad entre los estudios incluidos fue alta y, en los análisis agrupados de efectos aleatorios, el tabaquismo materno durante el embarazo incrementó la probabilidad de descendencia con sobrepeso (OR: 1,43; IC95%: 1,35; 1,52) y la diferencia media del IMC (β: 0,31; IC95%: 0,23; 0,39). En conclusión, los hijos de las madres que fumaron durante el embarazo tienen una mayor probabilidad de sobrepeso, así como una diferencia media del IMC, y estas asociaciones persisten en la etapa adulta.

Prenatal origin of obesity and their complications: Gestational diabetes, maternal overweight and the paradoxical effects of fetal growth restriction and macrosomia.

Pregestational (PGDM) and gestational (GDM) diabetes may be associated with a variety of fetal effects including increased rate of spontaneous abortions, intrauterine fetal death, congenital anomalies, neurodevelopmental problems and increased risk of perinatal complications. Additional problems of concern are fetal growth disturbances causing increased or decreased birth weight. Optimal control of maternal blood glucose is known to reduce these changes. Among the long lasting effects of these phenomena are a high rate of overweight and obesity at childhood and a high tendency to develop the "metabolic syndrome" characterized by hypertension, cardio-vascular complications and type 2 diabetes. Similarly, maternal overweight and obesity during pregnancy or excessive weight gain are also associated with increased obesity and complications in the offspring. Although there are different causes for fetal growth restriction (FGR) or for fetal excessive growth (macrosomis), paradoxically both are associated with the "metabolic syndrome" and its long term consequences. The exact mechanism(s) underlying these long term effects on growth are not fully elucidated, but they involve insulin resistance, fetal hyperleptinemia, hypothalamic changes and most probably epigenetic changes. Preventive measures to avoid the metabolic syndrome and its complications seem to be a tight dietary control and physical activity in the children born to obese or diabetic mothers or who had antenatal growth disturbances for other known or unknown reasons.

Maternal smoking during pregnancy and offspring growth in childhood: 1993 and 2004 Pelotas cohort studies.

OBJECTIVE: To explore the effects of maternal smoking during pregnancy on offspring growth using three approaches: (1) multiple adjustments for socioeconomic and parental factors, (2) maternal-paternal comparisons as a test of putative intrauterine effects and (3) comparisons between two birth cohort studies. METHODS: Population-based birth cohort studies were carried out in Pelotas, Brazil, in 1993 and 2004. Cohort members were followed up at 3, 12, 24 and 48 months. Multiple linear regression analysis was used to examine the relationships between maternal and paternal prenatal smoking and offspring anthropometric indices. In the 2004 cohort, the association of smoking with trunk length, leg length and leg-to-sitting-height ratio at 48 months was also explored. RESULTS: Maternal smoking during pregnancy was associated with reduced z scores of length/height-for-age at each follow-up in both cohorts and reduced leg length at 48 months in the 2004 cohort. Children older than 3 months born to smoking women showed a higher body mass index-for-age z score than children of non-smoking women. CONCLUSIONS: The results of this study strongly support the hypothesis that maternal smoking during pregnancy impairs linear growth and promotes overweight in childhood.

Maternal smoking during pregnancy and child overweight: systematic review and meta-analysis.

OBJECTIVE: Perform a systematic review of studies reporting on the association between maternal prenatal cigarette smoking and child overweight. DESIGN: Meta-analysis of observational studies. DATA SOURCES: Medline search and review of reference lists among studies published through June 2006. REVIEW METHODS: Included studies reported an association between maternal smoking during pregnancy and risk of overweight among children at least 2 years of age. We did not include in the meta-analysis studies that provided only a continuous measure of adiposity, although those studies are discussed separately. RESULTS: Based on results of 84 563 children reported in 14 observational studies, children whose mothers smoked during pregnancy were at elevated risk for overweight (pooled adjusted odds ratio (OR) 1.50, 95% CI: 1.36, 1.65) at ages 3-33 years, compared with children whose mothers did not smoke during pregnancy. The pooled estimate from unadjusted odds ratios (OR 1.52, 95% CI: 1.36, 1.69) was similar to the adjusted estimate, suggesting that sociodemographic and behavioral differences between smokers and nonsmokers did not explain the observed association. Although we observed evidence for publication bias, simulating a symmetric set of studies yielded a similar estimate (OR 1.40, 95% CI: 1.26, 1.55). CONCLUSIONS: Prenatal smoking exposure appears to increase rates of overweight in childhood. In parts of the world undergoing the epidemiologic transition, the continuing increase in smoking among young women could contribute to spiraling increases in rates of obesity-related health outcomes in the 21st century.