EFFECT OF AGE, SEX AND SMOKING-HABITS ON PNEUMOCOCCAL ANTIBODIES IN AN ELDERLY POPULATION

Background. Pneumococcal infections are a common cause of morbidity an d mortality among elderly people. Protection against pneumococcal infe ctions is mediated by serotype-specific antibodies to capsular polysac charides. To obtain an estimate oi anti-pneumococcal immunity, prevale nce and levels oi pneumococcal antibodies were studied in an unvaccina ted elderly population, Methods. IgG antibodies to pneumococcal seroty pes 3, 6A, and 8 and to cell wall polysaccharide (C-PS, a common antig en to all pneumococci) were measured by enzyme immune-assay in 480 sub jects aged 64-97 years (206 men, 274 women) who were a random sample ( 41%) oi elderly inhabitants in a semirural community in Finland. Resul ts. An average of 10% ei the elderly lacked antibodies to serotypes 3, 6A? and 8, and 62% of the elderly had them in low titres only. Anti-C -PS antibodies were found in 99% oi the elderly, and in significantly higher titres than anticapsular antibodies. Antibody titres to C-PS an d to type 6A decreased with age. Elderly women had significantly lower antibody levels than men. Among the men, current smokers had higher a ntibody titres than non-smokers: in the women, this analysis was not p ossible because oi infrequent history oi smoking. The effect oi smokin g on antibody titres was reversible a;ter cessation oi smoking. Conclu sions. A considerable proportion of the elderly lacked protective anti bodies to commonly infecting pneumococcal serotypes 3, 6A, and 8. Smok ing increased the prevalence and levels oi pneumococcal antibodies pro bably as a consequence ol numerous respiratory infections. These obser vations emphasize the importance of administration of the pneumococcal vaccine among the elderly.