Although our results were consistent after multiple adjustments and in sensitivity analyses, we cannot exclude residual confounding.
However, the effect of age remained clear even after multiple adjustments and subgroup analyses, which further consolidates the basic observation made in this report.
Some items were eliminated quickly, but others required multiple adjustments and rounds of questioning before they were either eliminated or included in the final questionnaire.
Removal of studies rated as lower quality, removal of studies with multiple adjustments, and application of a fixed-effects model (reducing the weighting for smaller studies) weakened the association.
Rerunning the analysis after removing those studies that used multiple adjustments over and above age, sex, and assay plate (18, 52) (leaving 11 study populations included in the analysis) weakened the (random-effects) association further (SMD = 0.086, 95% CI: −0.075, 0.247; P = 0.298).
For the continuous analysis, two steps of adjustments were used: 1) adjustment for sex only and 2) multiple adjustments for sex, serum cholesterol and triglycerides, BMI, smoking and exercise habits, and educational levels.
This study explored causality based on three approaches: comparisons between two cohort studies 11 years apart, multiple adjustments for confounders and maternal paternal smoking comparisons.
The objective of this study is 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 middle-income country birth cohort studies, the 1993 and 2004 Pelotas cohorts, in Brazil.
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.
In particular, the effect of opioid exposure was robust, and remained after multiple adjustments in cross-sectional and longitudinal studies.
Strengths of this study include the large sample size from a community-based cohort of African Americans, simultaneous volumetric quantification of PAT and VAT, and multiple adjustments for potential confounders.
