London's Pulse: Medical Officer of Health reports 1848-1972

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London County Council 1950

[Report of the Medical Officer of Health for London County Council]

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84
exercise. It is probable that a large proportion of the two-thirds reduction in our
phthisis mortality during the last fifty years is due to such agencies. What a splendid
effect a good town-planning scheme ought to exercise on the public health."
Prevalence and Mortality
From 1931 to 1939, the number of known tuberculous persons on the registers
of Tuberculosis Clinics in London fell from 40,000 to 30,000, but rose to 40,000
again during the war and post-war years though the ratio of lung cases to nonpulmonary
cases has changed considerably. Pulmonary cases have increased from
'29,560 in 1931, to 34,120 in 1950. Tuberculosis in other sites has fallen from 11,000
cases in 1931 to 5,600 in 1950. This reflects two separate trends ; first, better casefinding
and increased chronicity of lung tuberculosis, and secondly, as many nonpulmonary
cases were milk infections, a considerable improvement in the purity of
milk supplies of London.
There is little doubt that improved medical supervision of children and adults,
at school, at home and at work; better diagnostic facilities including X-ray and
tuberculin surveys, and a determined drive to examine the contacts of known cases
of tuberculosis, have contributed most to the increased registered numbers by
eliciting new cases of lung disease—even though the population has been decreasing
in size and even allowing for a considerable rehousing of tuberculous families out of
London. The reduced death-rate from the disease with its corollary, a longer life
during which others can be infected; the increasing daily contact between members
of London's population in streets, shops, crowds, transport vehicles and other public
places; and the housing shortage of the last 10 years has each played a part in
spreading infection and producing new cases. Since the advent in 1911 of compulsory
notification of newly discovered cases of tuberculosis, the annual recorded
incidence of these in London, both for pulmonary and for other forms, has, apart
from the war years, fallen steadily. New notifications of lung cases had been decreasing
until 1939 when the rate rose and remained raised until 1945 when it began
to fall again and it has not yet returned to the 1939 level.
New notifications among males, hitherto always higher, are tending in some
age groups to approximate to, and in the age group 5—14 years, even to fall below,
the rates for females. The slower pace of decline in the incidence of tubercle in
females is not a new problem but a serious one, the trend of which has been underlined
by recent statistical approach. Not only does this represent a gradual change
in the sex, age and other characteristics of the tuberculous population, but it may
be taken to reflect changes in the reasons and sources of recruitment to that demographic
group . The epidemiology of tuberculosis is not static; it is sensitive to all the
intricate, subtle and pervading social influences manifest in modern human populations
especially those living in big cities. The tables and graphs at the end of this
conspectus illustrate these trends in full detail.
Tuberculous meningitis which occurs mainly in young children might reasonably
be taken as a measure of infective hazard, human and bovine, in the home.
In London, since 1904, mortality from tuberculous meningitis which, until
streptomycin became available late in 1947, was uninfluenced by treatment, has,
apart from the war years, fallen steadily. The figures for meningitis incidence and
mortality appear, therefore, to be less a measure of infection in the whole community
than one of exposure hazard in the immediate family circle of the young children
concerned. This indicates that young children are now better protected against
infection in the home.
Eleven per thousand of London's population are known at the present time to
have active or quiescent tuberculosis. To this may be added four per thousand
presumed to be "at large" and as yet unrecognised. With a total tuberculosis
prevalence of 1.5 per cent. among the population and of these about a quarter capable