Publications

The definition of environment refers to external physical conditions that may affect human health (1), but the word is used in the medical literature with different connotations, both in English and in other languages. This generates confusion in the medical literature, when the role of environment is discussed in the context of disease etiology. In particular, research on the role of environment in human carcinogenesis suffers from this ambiguity. On the one hand, environment can encompass all non-genetic factors such as diet, lifestyle and infectious agents. In this broad sense, the environment is implicated in the causation of the majority of human cancers, as has been demonstrated since the 1960s (2). Such a broad meaning of the word environment is assumed when referring to gene–environment interactions . On the other hand, environmental factors can include only the (natural or man-made) agents and circumstances encountered by humans in their daily life, upon which they have no or limited personal control. In this sense, environmental factors are restricted to air, water, soil and food pollutants, including physical pollutants such as sources of ionizing radiation. These ambiguities in the terminology and the inconsistencies in the use of the vocabulary by cancer researchers contribute to public confusion regarding the role of the environmental causes of cancer. A distinction relevant to cancer prevention may be made between factors related to personal behaviors, lifestyle (e.g. tobacco smoking and alcohol drinking), involuntary exposures, such as those linked to air, water, soil or food pollutants, and occupation. It would be preferable to abandon the term environment and to use terms such as nongenetic or modifiable determinants of disease (broad sense of environment) and pollutants (narrow sense).

The prevalence of smoking in Italian males and females has been investigated using data from the National Health Survey (first cycle), collected between January and March 1994, and based on a total sample of 13,048 individuals (6,307 males and 6,741 females) representative of the general Italian population. Overall, 24.2% of Italians aged 15 years or over described themselves as current smokers (32.6% of males and 16.3% of females). Ex-smokers were 14.2%, including 22.3% of males and 6.6% of females; never smokers were 61.6% (45.1% of males, 77.1% of females). In both sexes, the highest proportions of smokers were young to middle-aged (35-44 years), and there was a substantial decline in smoking rates in the youngest age group (15-24 years), to reach 19.8% of males and 9.9% of females. A steady and substantial decline in reported smoking prevalence over time was observed in males (from 54.2% in 1980 to 32.6% in 1994), whereas smoking prevalence remained approximately stable around 17% in females. This was due to some increase in smoking prevalence among women over 35 years of age, following a cohort effect, and the low quit rate among females. The average number of cigarettes per smoker per day was slightly up, to reach 18.3 in males and 13.4 in females in 1994. The fall in reported cigarette consumption was only partly reflected in legal sale data, which showed for 1993 a consumption of 1.86 kg per adult per year, corresponding to 5.1 cigarettes per day. Taking into account also smuggling, this indicates that interview-based figures were underestimated by at least 25%. In males, but not in females, smoking was less frequent in northern and more developed areas of the country and among more educated individuals. Among Italians with a university degree, smoking rates were for the first time higher in females (31.5%) than in males (23.7%). Thus, the data from the 1994 National Health Survey confirm the long-term decline in smoking prevalence among Italian males, in the absence however of appreciable changes in females.

This study confirms the existence of and quantifies a number of strong socioeconomic correlates of cancer risk and indicates a few points open to additional investigation, such as the different pattern of risk for rectal and colon cancer, the strong negative gradient for endometrial cancer, and the absence of any clear association with education for cancers of the ovary, prostate, urinary tract, lymphomas, and myeloma.