Re: Consumption of Spicy foods in China may be a surrogate of regional differences in diet, lifestyle and environment
Thank you for the thoughtful comments. Indeed we have noted geographical variations and carefully controlled for the "center effect" due to multiple survey sites on the hazard function by stratifying on the survey site variable in the Cox model (stratified model). We have also adjusted the survey site variable in the model, and examined the association within each survey site and then pooled the results using meta-analysis. The results remained largely unchanged.
Competing interests: No competing interests