Interaction terms were checked for effect modification.
These variables will also be checked for effect modification.
Also, these variables will be checked for effect modification.
These variables will also be checked for effect modification at all measurement moments.
Effects of the intervention will be checked for effect modification (gender, type of work, number of ergonomic measures implemented).
Effects of the intervention will be checked for effect modification by experience and gender of the GPs.
For primary endpoints, we checked for effect modification by baseline values of CD4 cell count, BMI, and baseline ART use status (HAART naïve, on treatment for less or equal to 3 months, or on treatment for 3 to 6 months).
We also checked for effect modification by trimester of PAH monitoring, PAH monitoring season, or season of birth by including terms for the interaction between PAH and trimester of PAH monitoring, between PAH and PAH monitoring season, and between PAH and season of birth in separate models.
These variables (age, gender, education, and marital status) were also checked for potential effect modification, (adding interaction terms to the regression model).
We checked for significant effect modification by adding appropriate indicator variables to the models and compared nested models by using χ statistics.
Logistic regression was used to check for effect modification by covariates [mother's age and education, socioeconomic status, mother's age at first pregnancy, presence of male sibling younger than 3 (because of the perceived preference given to male children, their homes may be safer), and number of siblings].
