Twelve-month effectiveness of telephone and SMS support to mothers with children aged 2 years in reducing children’s BMI: a randomized controlled trial

BACKGROUND/OBJECTIVES: Few quality intervention studies have assessed whether a combined telephone and short message service (SMS) intervention to mothers is effective in reducing BMI and obesity risk behaviors of children at 3 years of age. This study aimed to assess effectiveness of telephone and SMS support in reducing children’s body mass index (BMI) and obesity risk behaviors. SUBJECTS/METHODS: A randomized controlled trial (RCT) with 662 women of 2-year-old children (with the proportion of overweight and obesity being similar to the general population) was conducted in Sydney, Australia, March 2019–October 2020. The mothers in the intervention group received three telephone support sessions plus SMS messages and mailed-intervention-booklets over a 12 months period i.e., 24–26, 28–30, and 32–34 months of the child’s age. Mothers in the control group received usual care and two mailed booklets on information not related to the intervention. The primary outcome was child’s BMI at 3 years of age. Secondary outcomes were children’s dietary and activity behaviors. All outcome measures were based on mothers’ self-report using standardized tools due to COVID-19 pandemic restrictions. RESULTS: 537 (81%) mothers completed the post-intervention assessment at 3 years with only 470 (71%) children having weight and height measures. Multiple imputation analysis showed no statistically significant difference in mean BMI between the groups. Children in the intervention group were more likely not to eat in front of the TV [AOR 1.79 (95% CI 1.17–2.73), P = 0.008], more likely to meet the dietary recommendations [AOR 1.73 (95% CI 0.99–3.02), P = 0.054] and meet the activity recommendations [AOR 1.72 (95% CI 1.11–2.67), P = 0.015] than those in the control group respectively. Among those with an annual household income (<AUD$80,000), the intervention was significantly associated with a lower mean BMI [16.26 (SD 2.22) kg.m(−2)] in the intervention group than [16.84 (SD 2.37)] in the control, a difference of −0.59 kg/m(2) (95% CI: −1.15 to −0.03, P = 0.040). CONCLUSIONS: A staged telephone and SMS support intervention to mothers with children aged 2 years was associated with improved dietary and activity behaviors. The intervention was also associated with reduced children’s BMI at age 3 years only for those from lower income households. TRIAL REGISTRATION: The trial is registered with the Australian Clinical Trial Registry (ACTRN12618001571268)