Effects of telephone support or short message service on body mass index, eating and screen time behaviours of children age 2 years: A 3-arm randomized controlled trial.

Background: Few randomized controlled trial (RCT) interventions targeted children's early risk behaviours using telephone or short message service (SMS) support.

Objective: To evaluate the effectiveness of telephone or SMS early intervention focusing on mothers' behaviours starting from late pregnancy to improve BMI, and eating and screen time behaviours of children aged 2 years in comparison with the control group.

Methods: A 3-arm RCT was conducted in Australia, 2017-2019. Two arms involved the interventions using nurse-led telephone or SMS support, delivered in nine stages from late pregnancy to age 2 years. The third arm was control. The primary outcome was children's objectively measured BMI and BMI z-score at 2 years. Secondary outcomes included child eating and screen time behaviours as reported by parents at 2 years.

Results: At 2 years, 797 mother-child dyads (69%) completed the telephone survey with 666 (58%) completing weight and height measurements. The study found no statistically significant difference in BMI between the groups. The mean BMI for telephone support was 16.93 (95% CI: 16.73 to 17.13), for SMS 16.92 (95% CI: 16.73 to 17.11) or for control 16.95 (95% CI: 16.73 to 17.16) with a difference of -0.02 (95% CI: -0.31 to 0.27, p = 0.907) in telephone versus control, and a difference of -0.03 (95% CI: -0.30 to 0.24, p = 0.816) in SMS versus control. Telephone support was associated with higher odds of no bottle at bedtime (adjusted odds ratio [AOR]: 2.99; 95% CI: 2.01 to 4.47), family meals (AOR: 2.05; 95% CI: 1.26 to 3.33), drinking from a cup (AOR: 1.89; 95% CI: 1.24 to 2.88), less screen time (<1 h/day) (AOR: 1.56; 95% CI: 1.10 to 2.23) and not eating dinner in front of the TV (AOR: 1.50; 95% CI: 1.09 to 2.06). SMS support was also associated with higher odds of no bottle at bedtime (AOR 2.30, 95% CI: 1.58 to 3.33) than the control.

Conclusion: The telephone or SMS support intervention had no significant effects on BMI, but was effective in increasing no bottle use at bedtime. Telephone support showed more effects than SMS on reducing screen time and eating behaviours.