In Africa when one looks at HIV infection rates , a pattern emerges.

Genetics & Environmental Health Week
Islam may be linked to reduced rates of HIV infection in Africa.

According to researchers in the United States, ” religious constraints on sexuality may have consequences for the transmission of sexually transmitted diseases.

“Recognizing that several Islamic tenets may have the effect, if followed, of reducing the sexual transmission of HIV,” P.B. Gray and colleagues at Harvard University tested “the hypothesis that Muslims have lower HIV prevalence than non-Muslims.

“Among 38 sub-Saharan African countries, the percentage of Muslims within countries negatively predicted HIV prevalence,” study data indicated. “A survey of published journal articles containing data on HIV prevalence and religious affiliation showed that six of seven such studies indicated a negative relationship between HIV prevalence and being Muslim.
http://www.thebody.com/content/art26340.html

Here is a study from 2002 by a Christian group showing Muslims with much smaller HIV infection rates

http://martinrothonline.com/MRCC11.htm

Following Islam can keep you healthier

Perhaps if Christians emulated Muslims in regards to modesty etc Christians could lower HIV rates too.