Mortality in the London Boroughs, 1950--52, with Special Reference to Respiratory Disease

Abstract

The total number of deaths during this period was not excessive by national standards, but a break-down by sex and age suggests that there were in fact some thousands of 'extra' deaths among males generally and in particular among the 45-64 age group. The All Causes Standard Mortality Ratios (S.M.R.), by age, sex, and borough were very similar to those of 20 yr. earlier. The outstanding feature of the analysis by cause of death was an excess (mounting rapidly with age) in the deaths from a group of respiratory diseases comprising bronchitis, pneumonia, cancer of the lung, and respiratory tb. Borough death-rates indicate an area of exceptionally high respiratory mortality (more than 50% above the national level) in the east-central region of London. This section suffered a similar excess relative to the rest of the country in an influenza year, in the year of the smog disaster, and in the preceding three 'normal' years. The possible effect on these findings of errors in death certification is discussed. The borough mortality rates correlate closely with indices of social status and crowding and, in a superficial sense, something between 80 and 90% of the variance of the borough S. M. R. for respiratory disease can be 'explained' by these social factors. When the relationships are examined more closely, however, it is found that they really explain very little, and that the bulk of the observed variation must be due to some other factor or factors - very possibly including atmospheric pollution. The statistics are, in fact, consistent with the hypothesis that air pollution, besides its well-known short-term effect, exerts an important influence on the long-term death-rates from respiratory disease (especially bronchitis), and a smaller influence on the mortality from heart disease.