Date Published: June 29, 2017
Publisher: Public Library of Science
Author(s): Niko S. Wasenius, Kimberly P. Grattan, Alysha L. J. Harvey, Nick Barrowman, Gary S. Goldfield, Kristi B. Adamo, Rebecca A. Krukowski.
Animal studies have suggested that maternal weight-related factors during pregnancy can program offspring physical activity in a sex-dependent manner. However, there is limited evidence in humans. The purpose of this study was to investigate the association between maternal gestational weight gain (GWG) and offspring total physical activity (TPA) level and to determine whether these associations are moderated by sex of offspring or maternal pre-pregnancy weight status.
We studied 56 boys (mean age = 3.7 years, standard deviation (SD) 0.5) and 57 girls (mean age = 3.5±0.5 years) enrolled in licensed childcare centers. TPA was objectively measured using Actical® accelerometers. Information on pre-pregnancy body mass index (BMI), GWG, and other maternal factors were collected with a maternal health questionnaire. Associations between GWG, as a continuous variable or categorically (inadequate, adequate, and excessive), and offspring TPA were analysed using linear mixed models to take into account the intraclass correlation between the clusters (childcare centers). Models were adjusted for gestational age, accelerometer weartime, socioeconomic status, and pre-pregnancy BMI status.
We found a significant sex interaction (P-value = 0.009). In boys, greater GWG was associated with decreased offspring TPA (β = -3.2 counts⋅1000−1/d, 95% confidence intervals (CI) = -6.4–0.02, P-value = 0.049). In girls born to mothers categorized as overweight or obese, the association between the GWG and TPA followed an inverted U-shape curve (β for GWG squared = -0.1 counts⋅1000−1/d, 95% CI = (-0.2 –-0.04), P-value = 0.005). In contrast, a U-shaped curve was found in girls born to mothers classified as lean (pre-pregnancy BMI<25 kg/m2) (β for GWG squared = 0.7 counts⋅1000−1/d, 95% CI = 0.2–1.2, P-value = 0.011). In boys, TPA in offspring was higher among women with inadequate GWG compared to adequate GWG (P-value = 0.0137), whereas no significant differences were found in girls (P-value = 0.107). Maternal GWG can be an important biological marker of offspring TPA. These findings support the sex-dependent early developmental programming influence of GWG on TPA.
Physical activity (PA) has been linked to numerous health benefits in children [1,2]. Unfortunately, awareness of these health benefits has not translated into sufficient increases in PA, as a substantial proportion of children do not meet the PA and sedentary behavior guidelines . The current Canadian early years movement guidelines for infants, toddlers, and preschool-aged children call for volume and do not specify intensity . Unfortunately, different intervention strategies and approaches aimed at increasing children’s volume of PA have proven to be relatively ineffective [5,6]. Further information is required about factors that regulate children’s PA behaviour to find more effective strategies to increase their PA levels [7,8].
Baseline characteristics of participants are presented in Table 2. As shown in Table 2, boys were significantly older, taller, heavier, and were more active than girls. No significant differences were found between sexes in maternal GWG, although mothers with male offspring were more likely to exceed GWG guidelines. We found no significant sex differences in child’s current BMI, maternal pre-pregnancy weight, gestational age, pregnancy complications, or SES. There were no significant differences in age, gestational age, birth weight, body height, body weight, BMI, TPA, or accelerometer weartime between boys and girls included in the analysis (n = 113) and those who were excluded (n = 54) (P > 0.05). Children who were excluded were those who had PA data but were missing data for other variables. SES status, which was only available from 28 (52%) of the excluded children, was significantly higher among included children (χ2 = 11.6, df = 1, P = 0.001).
In this study, we found that maternal GWG was independently associated with preschool-age offspring TPA in a sex-dependent manner. In boys, greater GWG was associated with decreased TPA independent of maternal pre-pregnancy BMI status. However, in girls, maternal pre-pregnancy BMI was found to moderate the relationship between GWG and TPA. In mothers who were overweight or obese, the association between the GWG and TPA followed an inverted U-shaped curve, which reached its highest point when GWG was equal to 18 kg. In contrast, a U-shaped curve, which peaked when GWG was equal to 11 kg, was found in mothers who were underweight or normal weight before pregnancy. Additionally, in boys, TPA was found to be higher among the offspring of mothers with inadequate GWG. In girls, TPA did not differ between inadequate, adequate, excessive GWG categories. Findings from the present study support the sex-dependent role of maternal GWG as a predictor of offspring TPA.
In conclusion, the findings of the present study provide preliminary evidence that maternal GWG is independently associated with TPA in preschool-aged offspring in a sex-dependent manner. Our data suggest that GWG, which has been previously associated with risk of downstream disease in offspring [22–24], could be a risk factor for physical inactivity. Our findings support future intervention research to determine whether managing GWG in hopes of optimizing developmental programming will have a positive impact on offspring PA.