Increased life span and decreased weight in hamsters exposed to cigarette smoke

Five groups of fifty-one 2-month-old male Syrian golden hamsters received three 10-minute exposures to cigarette smoke per day, 5 days per week, for the duration of their lives. Three of the groups were also chronically exposed to aerosols of chrysotile asbestos, cobalt oxide, and nickel oxides, respectively. The fourth group received twelve weekly injections of 0.25 mg of diethylnitrosamine. The smoke-exposed groups lived significantly (P less than .01) longer than their sham-exposed cohorts and untreated controls. Their mean body weights were significantly (P less than .01) lower than in the sham-exposed groups. The hypothesis is proposed that delayed onset of amyloidosis and lower body weight in the smoke-exposed hamsters may have been responsible for their increased life spans. It is hypothesized that cigarette smoke affected the immune system of the animals, resulting in retardation of amyloidosis, a frequent cause of death in hamsters.