title: Effect of age, sex and smoking habits on pneumococcal antibodies in an elderly population.
abstract: BACKGROUND
  Pneumococcal infections are a common cause of morbidity and mortality among elderly people. Protection against pneumococcal infections is mediated by serotype-specific antibodies to capsular polysaccharides. To obtain an estimate of anti-pneumococcal immunity, prevalence and levels of pneumococcal antibodies were studied in an unvaccinated elderly population.
  
  
  METHODS
  IgG antibodies to pneumococcal serotypes 3, 6A, and B and to cell wall polysaccharide (C-PS, a common antigen to all pneumococci) were measured by enzyme immuno-assay in 480 subjects aged 64-97 years (206 men, 274 women) who were a random sample (41%) of elderly inhabitants in a semirural community in Finland.
  
  
  RESULTS
  An average of 10% of 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% of the elderly, and in significantly higher titres than anti-capsular antibodies. Antibody titres to C-PS and to type 6A decreased with age. Elderly women had significantly lower antibody levels than men. Among the men, current smokers had higher antibody titres than non-smokers; in the women, this analysis was not possible because of infrequent history of smoking. The effect of smoking on antibody titres was reversible after cessation of smoking.
  
  
  CONCLUSIONS
  A considerable proportion of the elderly lacked protective antibodies to commonly infecting pneumococcal serotypes 3, 6A, and 8. Smoking increased the prevalence and levels of pneumococcal antibodies probably as a consequence of numerous respiratory infections. These observations emphasize the importance of administration of the pneumococcal vaccine among the elderly.
authors.affiliation: National Public Health Institute, Department in Oulu, Finland.
authors.forename: U
authors.initials: U
authors.lastname: Sankilampi
authors.forename: R
authors.initials: R
authors.lastname: Isoaho
authors.forename: A
authors.initials: A
authors.lastname: Bloigu
authors.forename: S L
authors.initials: SL
authors.lastname: Kivelä
authors.forename: M
authors.initials: M
authors.lastname: Leinonen
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000907:Antibodies, Bacterial / Q000032:analysis*; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000276:immunology; D016001:Confidence Intervals; D003625:Data Collection; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology* / Q000276:immunology*; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial