So, I've looked at two more datasets in examining this phenomenon which started with noting that gay men were more likely to be in excellent health than straight men in the California Health Interview Study (CHIS).
Many thanks to Randy Sell at Drexel who has collated information on a large number of national and state-level studies that ask people about their sexual orientation and/or sexual partners at www.gaydata.org.
In the General Social Survey (GSS), a large telephone survey that has been on-going since 1972, they asked about the sex of respondent's sexual partners in the last year, the last 5 years, and since age 18, in various combinations since 1988. (I used this same dataset to look at the phenomenon of gay men giving blood, which can also be considered as an indicator of well-being).
In the GSS, 33% of men who had sex exclusively with other men over the prior five years (26%-40%) were in excellent health, virtually identical to the 33% (31%-34%) of men who had sex exclusively with women over the prior five years.
Looking at sexual partners just in the last year, 35% of men who had sex only with men in the previous year (29%-42%) were in excellent health, about the same as 34% (33%-35%) as men who had sex only with women in the previous year.
In the National Household Survey on Drug Abuse (NHSDU), on on-going telephone survey used to understand drug use in the US, they asked about sexual partners in one year, 1996. For reasons I don't understand, they never asked before or since. If they had, this survey could have been one of the best sources of information on LGB population health.
52% of the 58 men who reported sex only with males were in excellent health (39%-65%), which is much higher than the 36% of the 3,196 men who reported sex only with women (35%-38%).
The proportion of men who had sex with men who reported excellent health in this survey was a lot higher than in other surveys, too, so I'd be a little cautious in putting much faith in these particular results.