This study seems to go quite a ways towards answering your question:

Among both U.S. white and black men, physicians were, on average, older when they died, (73.0 years for white and 68.7 for black) than were lawyers (72.3 and 62.0), all examined professionals (70.9 and 65.3), and all men (70.3 and 63.6). The top ten causes of death for white male physicians were essentially the same as those of the general population, although they were more likely to die from cerebrovascular disease, accidents, and suicide, and less likely to die from chronic obstructive pulmonary disease, pneumonia/influenza, or liver disease than were other professional white men...

These findings should help to erase the myth of the unhealthy doctor. At least for men, mortality outcomes suggest that physicians make healthy personal choices.

-- Frank, Erica, Holly Biola, and Carol A. Burnett. "Mortality rates and causes among US physicians." American journal of preventive medicine 19.3 (2000): 155-159.

You may also find this worth checking into:

The doctors had a lower mortality rate than the general population for all causes of death except suicide. The mortality rate ratios for other graduates and human service occupations were 0.7-0.8 compared with the general population. However, doctors have a higher mortality than other graduates. The lowest estimates of mortality for doctors were for endocrine, nutritional and metabolic diseases, diseases in the urogenital tract or genitalia, digestive diseases and sudden death, for which the numbers were nearly half of those for the general population. The differences in mortality between doctors and the general population increased during the periods.

-- Aasland, Olaf G., et al. "Mortality among Norwegian doctors 1960-2000." BMC public health 11.1 (2011): 173.

EDIT: I added a second study and cleaned up the citations.