1 Ingram School of Nursing, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada. andraea.vanhulst@mcgill.ca.
2 Ingram School of Nursing, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada.
3 Department of Mathematics and Statistics, Faculty of Arts and Science, Concordia University, Montreal, QC, Canada.
4 PERFORM Centre, Concordia University, Montreal, QC, Canada.
5 Department of Human Sciences, Human Development and Family Science Program, Couple and Family Therapy Specialization, College of Education and Human Ecology, The Ohio State University, Columbus, OH, USA.
6 Department of Surgery, The Ohio State University Wexner Medical Centre, Columbus, OH, USA.
7 Department of Pediatrics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.

Background: Impaired family functioning has been associated with obesity in children and adolescents, but few longitudinal studies exist. We examined whether family functioning from early to mid-childhood is associated with overweight and obesity in later childhood and adolescence.

Methods: We examined data from the Quebec Longitudinal Study of Child Development (QLSCD), a birth cohort (N = 2120), collected between 1998 and 2011. Parent-reported family functioning was assessed at 4 time points between ages 0.5 and 8 years using the McMaster Family Assessment Device with established cut-offs for impaired family functioning. Participants were classified as having experienced: 1) early-childhood impaired functioning, 2) mid-childhood impaired functioning, 3) both early and mid-childhood impaired functioning, or 4) always healthy family functioning. Overweight and obesity were determined at 10- and 13-years using WHO criteria. Covariate adjusted multinomial logistic regressions were fitted to the data to examine associations between longitudinal family functioning groups (using the always healthy functioning as reference category) and the likelihood of having overweight and obesity (vs normal weight) at ages 10 (n = 1251) and 13 years (n = 1226).

Results: In the 10- and 13-year sub-samples, respectively 10.2% and 12.5% of participants had experienced both early and mid-childhood impaired family functioning. Participants in this group had an increased likelihood of having obesity (vs normal weight) at age 10 years [OR = 2.63 (95% CI: 1.36; 5.08)] and at age 13 years [OR = 1.94 (95% CI: 0.99; 3.80] compared to those in the always healthy functioning group. No associations were found for other family functioning categories or for overweight status.

Conclusion: Approximately one in ten children experienced impaired family functioning throughout early and mid-childhood. Findings suggest a link between impaired functioning across childhood and the development of obesity at 10 years of age and possibly at 13 years of age.