CVA is more likely to get early in the morning and in winter. Bronchial asthma may aggravate at night. Some psychological diseases worsen on fullmoon days. Why is that?
I don't research in this area however I have read certain things related to this. For example, individuals suffering with depression feel worse at Winter when we have less hours of daylight. Also, in humid climates, people with autoimmune diseases, specifically those with lupus and Rheumatoid Arthritis, suffer much worse.
Might not be helpful but thought I'd contribute the little I know anyway :)