Ecological studies in Pinar del Rio Province support a toxico-nutritional etiology of epidemic neuropathy in Cuba
Sammanfattning
To study risk factors of epidemic neuropathy with ecological study design, we
used surveillance data to calculate cumulative incidence in 59 small areas
in the most affected part of Pinar del Rio Province, Cuba. The rates ranged
from 2 to 55 per 1000 inhabitants and focus group discussions consistently
revealed that rural high rate areas had a monotonous carbohydrate diet because
of decreased state food rations and poor access to unofficial food
production due to dense populations and state tobacco production. Adjacent
low rate areas had a more diverse diet due to lower population densities and
private agriculture with surpluses sold on the unofficial market. Analyses of
digitalized land tenure maps confirmed higher (p<0.05) neuropathy rates in
state tobacco areas as compared to private agriculture areas.
The epidemic peak was preceded by the lowest ever distributed rations of
meat and egg. Vitamin supplementation in March was followed by incidence
decline in May. Access to the unofficial food market for urban families was
estimated by family doctors using an economy index. Only one (3%) of 32 families
with an index +2 SD above the mean had neuropathy compared to 186
(22%) of 859 families with average economy. The neuropathy rate among
the 7 700 pregnant women in the province who received extra meat and milk
rations, was 0.5/1000, whereas the rate in fertile-age non-pregnant women
was 33/1000. The consistent association of monotonous carbohydrate diet
and the resulting unbalanced nutritional status, aggravated by tobacco smoking
is the most probable causes of the neuropathy affecting about 50 000
Cubans in 1992-93.