Strengths and limitations
Strengths included the use of an RCT to test an evidence-informed intervention. We published the study protocol [However, the generalizability of this study may be limited due to the use of existing study participants who could be highly committed to a public health research program. We were also unable to carry out weight and height measures objectively by RAs through home visits as planned due to the COVID-19 pandemic. The use of mail-out of measurement tools for parents to measure was an alternative option under extenuating circumstances. It is likely that the measurement errors would be balanced out by the RCT design. The complete-case analysis for BMI may be under-powered to detect the intervention effect as we did not reach the required sample size (