A study of more than 66,000 nurses between the ages of 30 and 55 indicated that smoking lowers the age of the natural menopause. Furthermore, there is strong evidence of an association between smoking and cancer of the cervix. Smoking also has more immediately bad effects on pregnant women, their foetuses, and nursing mothers. It increases the likelihood of miscarriage and stillbirth, and may result in low birth-weight and backward babies. Both the quality and quantity of breast milk may be reduced if the mother smokes.
The results of a Canadian survey showed that the relative risk of disability was 1.25 times higher in women who were current or former smokers compared with non-smokers. Almost 12% of the days taken off work because of sickness in Canada are attributable to smoking: smoking accounts for 19.4 million 'disability' days every year, or 2.65 days per year for each woman aged between 15 and 64. Similarly, in the USA, it was estimated that cigarette smoking accounted for 18% of all newly diagnosed cancers in women and for a quarter of all cancer deaths in 1980.
Statistics about women and smoking in the developing world are strikingly similar to those seen in surveys of Western women 20 years ago. In poor countries it is literate women, possibly of the middle, professional classes, who smoke and who see the habit as a symbol of being modern and moving with the times. Industrialization and more money to spend also affect the smoking habits of women. In Nigeria, for example, there have been few women smokers up to now because there are many socio-cultural influences that inhibit the habit among women, but as women's literacy and their access to cash increases, the influence of Western culture grows, and the latest surveys in Nigeria show a considerably higher incidence of smoking among women than before.