Birth distance influential factors: a multilevel recurrent events approach.

BACKGROUND The study was developed in order to find a subset of potential factors, which affect birth distance pattern, regarding consideration on correlation of events of birth in a family and correlation within clusters/centers which other studies omit these correlations. METHODS Referring to documents that were registered for family in the health care centers on socio-economical zone, we consider the families with at least one successful birth. Data were drawn from four health care centers, which selected via 27-health center in Hamedan City, western Iran, each from a socio-economic zone. It was expected, same socio-economic status family have same specific birth distance and a family follows a specific pattern. The multilevel recurrent approach was conducted to analyze the sample. The sample was 480 families and 1115 birth events occurred in these families. RESULTS The final step model shows that significant factors on the birth distance time were mothers job (P=0.018). The random effect of second level (clusters/centers) was significant (P=0.038). In other words, the socio-economic of family affects on the birth distance patterns. Other potential variables were not significantly affected birth distances and were deleted from the final model. CONCLUSIONS There are many potential factors, which may affect to birth distance, but multilevel recurrent event model has a better fit to data because of frailty and center effects. Application of other model such as Cox and frailty models may result in misleading reports.