View report page

With bronchitis the sex differential is much more in evidence at all ages, though the
rates below 45 years are based on small numbers of deaths and are not statistically significant.
At ages 45.64 years the male rate is five times the female rate and at age 65 years
and over it is two and a half times—both highly significant differences.
This large sex differential appears to be a characteristic of this century; the following
figures giving a more detailed age split show how it has developed:

These figures are matched by somewhat similar, though slightly lower, ratios for England
and Wales.
A partial explanation may lie in the factor of smoking habits, particularly cigarette
smoking. The association between lung cancer and smoking has been clearly demonstrated
in the last decade and more recently smoking has been under suspicion as an aggravating
factor in bronchitis. Smoking received a tremendous impetus in the first world war and
the consumption of tobacco again increased between 1938 and 1945. Although the figures
above for the age group of 45 and over as a whole show that the sex differential is continuing
to increase, a glance at the figures for individual age groups indicates that the differential
is tending to shift towards the later ages; for the 45.54 age group there has in fact been
a decline since 1947, whereas for the age group 55.64 there has been an increase of about
one half, for 65.74 an increase of about seven.tenths and for 75 years and over the differential
has doubled.
This relative shift of the differential to later ages could equally well be associated with
the extension of smoking among women—a practice which has followed that of men
both as regards time and quantity. Other things being equal one might expect that the
male/female ratio would, as time goes by, tend to decrease at later ages but as the bronchitis
death rate for both sexes has been declining in recent years it is possible that this may
affect the relativity.
As indicated earlier, unlike pneumonia, bronchitis is a disease from which a person
may have suffered for many years before death. This is evident from the morbidity statistics
produced by the Ministry of Pensions and National Insurance, based on claims for sickness
benefit. Certificates in support of such claims now cover practically the entire employed
male population, but they are not so representative of the female population because only
married women who follow a paid employment are eligible for national insurance and,
of those that are, two.thirds of them ' opt out' of the scheme for sickness benefit.
The latest Digest of statistics analysing certificates of incapacity ', relating to 1956.57,
show that, for both sexes, bronchitis was one of the two most common causes of sickness
absence (for which a claim was made) and was the reason for the highest number of days
of absence. The other most important cause of absence was influenza, which fluctuated
from year to year whilst bronchitis is more consistent. In terms of days, bronchitis was
responsible for some 20 million days of sickness benefit or 11 per cent, of the total in Great
Britain; the corresponding figures for females were some four million days, five per cent,
of the total.
Bronchitis and environmental factors in London—It is clear that bronchitis is important
where both mortality and morbidity are concerned. As regards the latter it is not possible
to compare London experience with national or regional figures but in relation to mortality
11