Richard Coker, Martin McKee, Rifat Atun, Boika Dimitrova, Ekaterina Dodonova, Sergei Kuznetsov et al
Coker R, McKee M, Atun R, Dimitrova B, Dodonova E, Kuznetsov S et al.
Risk factors for pulmonary tuberculosis in Russia: case-control study
BMJ 2006; 332 :85
doi:10.1136/bmj.38684.687940.80
Milk is probably not the leading danger
Dear Editor,
The short article 1 is a good example of simple analysis of the
complex problem which was never done in Russia. While applaud to this
report I want to add some doubts to the cautious concluding part of the
report. From the report it is not clear what method was used to produce a
sample of the population of the city. If it was the best available -
random sample from the voting lists – it would be a sample
underrepresenting the poor people without permanent housing (called “bomj”
in Russia). Other sample would be even more biased. On the other side is
not clear the proportion of cases (receiving the DOTS) of all patients
diagnosed tuberculosis.
The final selection of the most important risk factors is based on
calculation of the population attributable risks (PAR). It is a risky
exercise when reliable population prevalence is not known. Authors used
the prevalence in the control group, but do not provide these prevalences
in the report. In big cities of Russia most of the milk products is
pasteurized. In Moscow and in smaller proportion in other big cities
sterilized milk is sold at least in the same volumes as pasteurized.
Surveys show that people usually do not quite sure what is the difference
and what kind of product they buy. The consumption of non-pasteurized milk
is a marker of living in rural area, or in the remote poor parts of the
cities and being poor. People who buy non-pasteurized milk usually know
that it must be boiled. The questionnaire used probably asked subject
about using packed milk. If it is true, then “use of unpasteurized milk”
is only another index of poverty, and not most important one, because it
was brought to the first place only by PAR.
If these doubts are reasonable, then poverty and imprisonment will be
the leading risks, what is especially important in times when pre-trial
incarceration became more and more frequent, and inequality growing in
Russia.
Reference List
(1) Coker R, McKee M, Atun R, Dimitrova B, Dodonova E, Kuznetsov S
et al. Risk factors for pulmonary tuberculosis in Russia: case-control
study. Brit Med J 2006; 332(7533):85-87.
Competing interests:
None declared
Competing interests: No competing interests