all four countries where the data were complete. About half the deaths from malignant neoplasms were of unspecified site (range 31% in Mauritius to 65% in Thailand). Restricting to deaths with the site specified, carcinoma of the lung predominated in most of the countries, while carcinoma of the stomach also appeared to be important in Guatemala and Mauritius. In females malignant tumours of breast, uterus and cervix accounted for a high proportion of neoplcsms of specified site, although carcinoma of the lung was often equally important. In Egypt, 28% of neoplasms of specified site in females were of the breast and 15% of uterus or cervix. For Guatemala the corresponding proportions were 6% and 30%. These differences in proportions may ieflect real differences between countries, but may also be affected by different levels of reporting for different sites. Cultural factors may be important in this context, and under-diagnosis of genital tract diseases in women, for example, may be common in muslim societies. Chronic liver disease and diabetes appeared on the list independently from other gastro-intestinal and other endocrine disorders in most of the countries. "Genito-urinary causes" consisted mainly of cises of nephritis or nephrosis, while chronic obstructive airways diseases accounted for much of the "other respiratory diseases" category. It is surprising to see protein-calorie malnutrition recorded as an important cause of adult deaths in Guatemala.

Cause-specific mortality should be considered separately for different age groups whenever possible, as the importance of some diseases varies with age. In Egypt, for example, circulatory diseases accounted for 30% of deaths in those aged 15-44 years, but for 46% in those aged 45-64 years. The equivalent percentages for deaths from external causes were 19% and 4% respectively. Overall, for ages 15-64, 10% of deaths were due to external causes. If this were the only value considered, the great importance of external causes in the younger age groups might not be clear.

Similarly, when mortality data for both sexes are considered together, as in Table 2, maternal causes (which include all deaths relating to pregnancy, childbirth, or the puerperium, including those due to abortion) usually do not feature in the list of leading causes of death, whereas if data for females are considered separately, maternal causes frequently rank quite highly. This is illustrated in Table 3, which shows the data for Guatemala and Egypt by sex. In females, maternal causes appeared in the leading ten causes of death, although their importance is still likely to be underestimated because maternal mortality is generally under-reported. Deaths in early pregnancy are often misclassified and deaths related to abortion may be concealed. Thus, a survey conducted in Menoufia, Egpyt, found 382 of 1979 deaths (19.2%) among females to be due to maternal causes (Grubb et al, 1988). When the death certificates were examined, however, only 121 (6.1%) of the 1979 were reported as maternal deaths. Many of the remaining deaths were classified under circulatory diseases on the death certificate.

Other sex differences are apparent when data for males and females are analysed separately. For example, deaths due to accidents and violence are usually more common in males, although in Egypt deaths due to accidents involving fire are considerably more common in females. Cirrhosis and other chronic liver diseases appear to be more common in males.

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