52-year follow-up of a birth cohort reveals a high pneumonia incidence among young men

Background Knowledge of pneumonia incidence and risk factors in adults is mainly based on clinical studies of selected patient data and registers with aging populations. Prospective population-based investigations, such as birth cohort studies, are needed to understand pneumonia incidence and risk factors among the young and working age populations.

Methods Northern Finland Birth Cohort (NFBC) 1966 data (n=6750) was analysed for pneumonia incidence and risk factors. Incidence analysis was replicated using data from an independent NFBC 1986 cohort (n=9207). Pneumonia in relation with chronic conditions and lifestyle factors were analysed.

Results A peak with a maximum of 227 pneumonia episodes per 10 000 among men between the ages of 19 and 21 years was found in two independent cohorts. Pneumonia was associated with male sex (RR 1.72, 95% CI 1.45–2.04, p<0.001), low educational level (RR 2.30, 95% CI 1.72–3.09, p<0.001), smoking (RR 1.55, 95% CI 1.31–1.84, p<0.001), asthma (RR 2.19, 95% CI 1.73–2.75, p<0.001), cardiovascular diseases (RR 2.50, 95% CI 2.04–3.07, p=0.001), kidney diseases (RR 4.14, 95% CI 2.81–6.10, p<0.001), rheumatoid arthritis (RR 2.69, 95% CI 1.80–4.01, p<0.001), psoriasis (RR 2.91, 95% CI 1.92–4.41, p<0.001) and type II diabetes (RR 1.80, 95% CI 1.34–2.42, p<0.001). Men with excessive alcohol consumption at age 31 were at risk for future pneumonia (RR 2.40, 95% CI 1.58–3.64, p<0.001).

Conclusions Birth cohort data can reveal novel high-risk subpopulations, such as young males. Our study provides understanding of pneumonia incidence and risk factors among the young and working age populations.