The effect of urbanization on health in a mining area of Sierra Leone

Abstract

The effect of urbanization on health was studied in the Northern Province of Sierra Leone by comparing levels of health in the industrial new town of Lunsar with those of the villages of similar tribal composition, in the surrounding region. In order to do this a 10% sample census of Lunsar was made, and on this as a frame, a 4·0% clinical sample of all Lunsar was examined. The population of Lunsar was 9,540 on 31 July 1959. From the census and clinical samples, the population and its characteristics were defined, and rates of morbidity, fertility and survival were calculated. Data were also collected on environmental conditions such as housing, including overcrowding, water supplies and the disposal of human waste. The 4 villages studied were situated 7–20 miles from Lunsar. Total populations were seen in 3, and a half sample was taken of a fourth, a total of 1,010 persons. Census and clinical examinations were carried out in a manner similar to that in Lunsar, and the village populations were found to resemble each other in structure, civil state, and other factors as well as morbidity and survival rates. Data on environmental conditions were also collected. The material from the 4 villages was combined and compared with Lunsar. In population structure, Lunsar is more evenly balanced between the sexes, there being a female predominance in the villages, which also have more persons under 15 years and over 50, and fewer aged 20–39, with a comparative shortage of males. Half the males aged 20–35 in Lunsar, were married compared with 75% in the villages. 93% of females in Lunsar and all females in the villages in this group were married. Twice as many marriages were polygynous in the villages as in Lunsar. The villagers are mainly farmers whereas in Lunsar working for industry is the commonest male occupation. In environment, Lunsar has more overcrowding than the villages, but very little more than its nearest rival. The houses in Lunsar are bigger in size and number of rooms and better constructed than those in the villages. There is piped unpurified water in Lunsar but only contaminated streams or ponds in the villages. For morbidity rates in the two situations direct standardization was used in view of the differences in population structure. For malaria, onchocerciasis and nutritional deficiency the town has a more favourable experience than the villages; for the DMF rate the town is worse. For fertility and survival the crude birth rate and general fertility rates are higher for Lunsar, but on standardization, Lunsar has fewer expected births per female than the villages. This is supported by an examination of family size, when it can be shown that the mean for Lunsar is 4·7 compared with 5·6 in the villages. The infant mortality and stillbirth rates for the town are lower than for the country, and the infant/toddler deaths ratio is more favourable in Lunsar. In comparison with the village the town is well served by medical and public health services. As a result of these studies it may be stated that for Africans of the same tribal groups, the effect of urbanization is favourable for the viability of the population, for the physical environment and in the morbidity experience for the conditions studied. Thus the effect of urbanization on health is favourable in this mining area of Sierra Leone, in most important and relevant respects.