[0] http://link.springer.com/article/10.1007/s00406-003-0397-6#p...
I suspect that it's significant that the number of suicides over age 75 for men has dropped in those 15 years. Either reflecting a better quality of life, or a change how men are able to find satisfaction post-career.
[1] Ok. I'm making assumptions based on "traditional" gender roles here. But given the age group in question, I feel its justified. The division between male and female roles is far more present in those over 75 than the current working generations. This will change as the population ages, and be less applicable in 20-40 more years. But it's still applicable to this group today.
For women, when their husband dies, it's almost no big deal for most of them. They just continue on with their social group, and they can live for decades.
For men, when their wife dies, they usually die very quickly after (and not usually by outright suicide either).