Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Comparison of explanatory variables with the no gift group in multivariate analysis. Values are adjusted mean differences and corresponding 99.9% confidence intervals (data are reported in supplementary appendix 4). Threshold P=0.001 (Bonferroni correction for P=0.05/(9×5)=0.0011). ACE=angiotensin converting enzyme
