[Analysis of mortality in relation to various demographic phenomena: migration and marital status]

Abstract

This paper analyzes the mortality of major respiratory cancers, certified in Italy in the years 1981-84, by two demographic phenomena: migration and civil status. Direct standardized rates were computed using the total population as reference; a partial analysis of mortality by all causes was also performed. Because of the industrial development in some areas of Italy, great migrations took place in the past within the country, with specific and well known geographic and time patterns. This paper mainly considers migrations towards the industrialized regions of the north-west both from the north-east, occurring between the two world wars, and from the south regions, occurring from the fifties to the seventies. Various studies have shown that cancer mortality decreases with the geographic latitude of the area studied, and that there is a protective effect associated with being born in the southern part of the country. Italian regions were grouped into five areas: north-west, north-east, north-central, south-central and south. Individuals born in the same area of the last residence were defined as "stable", while "migrant" indicates that the area of birth differed from the last residence; for "internal migrant" both regions of birth and last residence are in the same area. For migrants to the north-west, rates by age are reported. For larynx cancer, only mortality of males is discussed. Our study's results confirm that lung cancer mortality is always higher for migrants than it is for stables from the same birth area. Immigrants also show higher rates of lung cancer mortality than the stables in the host areas. The rate ratio of emigrants versus stables in the birth area increases towards the south. The increasing protective role of birth area with decreasing latitude is confirmed for both stables and immigrants. Subjects in the north-west who emigrated from the north-east show age-specific mortality rates higher than stables, both in host and birth areas. Immigrants from southern areas show rates equal to the stables of the host area with increasing age. Results for lung cancer mortality suggest that migrants differed from the stables in socio-economic characteristics not only in the birth areas but also in the host regions. For larynx cancer, migrants and stables show similar rates. Mortality rates for internal migrants and stables decrease with latitude; the protective role of birth area in immigrants is less evident.(ABSTRACT TRUNCATED AT 400 WORDS)