I am not surprised by this at all, I bet many other disorders can be linked to the parents age at time of conception as well. To me it is logical as when we age all of our health is deteriorating, some faster then others due to lifestyle changes.
I would never tell any one no you can not have a child as it is not my place to do so. I would advise any older couple (35 plus) to start reading up on the percentage of birth issues that are directly related to age/health. There is no guarantee one way or the other and one needs to think about you life circumstance at the time ie food quality you are eating and stress in you life or your job. All this must be thought of if you are swilling beer and smoking like a chimney and diet is fast food. how would you expect to have a healthy baby as the material being put is is highly contaminated and of low quality.
I find this to be a very interesting and compelling study. It sounds like they tried to eliminate as many mitigating factors as they could. I would really like to read the official study. I'm going to have to hunt it down. It definitely warrants further research. I am going to have to pay closer attention to the parentage of my bi-polar patients. It will be interesting to see if the theory holds.
Please do keep us informed of what you find alskann. I think the effects of aging have been studied and many great associations found but is not an issue doctors address to their patients. I had a Asian doctor who studied in Scotland and he advised my wife on their first meeting in the importance of age and diet if she was to ever consider bearing children. He was as friendly as a rattle snake but cared about the health of his patients. I would be wiling to wager you will confirm the study.