Serum immunoglobulins and cognitive status in the elderly: i. A population study.

Fifty-seven cognitively impaired elderly had significantly elevated serum IgG (P less than or equal to 0.005) and IgA (P less than or equal to 0.01) levels and similar IgM levels, compared to a population of 65 elderly matched for age and sex, who did not manifest cognitive impairment. These findings are compatible with a current hypothesis that immunological factors may be important in the cognitive disorders observed with increasing frequency among the aged.