Study of mortality from pulmonary tuberculosis in Ontario between 1881 and 1961 reveals a steady decline in rates since the beginning of this century, affecting both sexes and all age groups. This decline has been much faster in the younger than in the older age groups. When the mortality rates are studied for groups of men and women born within 10-year periods (10-year cohorts) an orderly pattern of mortality emerges, consisting of two distinct phenomena. First, the shape of the "cohort" curves is always similar: the mortality rates rise sharply in childhood and the peak is reached in early adult life, followed by a gradual descent. This appears to be a basic but unexplained feature of pulmonary tuberculosis. Secondly, each cohort shows through its life span a lower mortality rate than the previous cohort, but a higher rate than the succeeding one; it is suggested that this is primarily due to a decline in intensity of tuberculous infection over the past several decades. The high tuberculosis rates seen now in the elderly are but the residue of the much higher rates experienced by these people early in their lives.

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PubMed1963

CARCINOMA OF THE LUNG: THE CHANGING PATTERN OF MORTALITY IN ONTARIO.

Study of the mortality rates for carcinoma of the lung in men in Ontario between 1931 and 1959 reveals a rise from 3.7 in the early 1930's to 26.7 per 100,000 in the late 1950's. Analysis of age-specific mortality rates in five-year cohorts (groups of men born within five-year periods) shows that (1) mortality rates in each cohort rise rapidly after the age of 40, ascending in the later years of life almost as a straight line; (2) each succeeding cohort experiences an appreciably higher mortality rate than the preceding one. Mortality rates in individual cohorts in Ontario are compared with those in England; the shape of the cohort curves, and the rate of the increase in mortality from cohort to cohort, are almost identical. However, the picture in Ontario appears to be lagging some 10 years behind. The mortality rates for men in Ontario born around the year 1890 are almost identical with those shown by men born in England around 1880. The rates for carcinoma of the lung will almost inevitably continue to rise in Ontario for at least the next 10 to 20 years.

Adult↗

PubMed1961