Non-occupational factors in occupational morbidity and mortality

This report forms a background paper for a World Health Organization document on "Assessment of the role of lifestyles in influencing workers' health risks". It identifies occupational and non-occupational factors which contribute to occupational mortality and morbidity. Eight categories of mortality and morbidity are identified as priorities for discussion, based on UK data. These are cardiovascular disease; lung cancer; chronic obstructive pulmonary disease; occupational deafness; dermatitis; vibration white finger; tenosynovitis; and suicide. Non-occupational factors associated with these include age, sex, race, smoking, social class, alcohol consumption, diet, exposures in leisure time, exercise, atopy, heredity, personal hygiene, personality type, stress, past or predisposing illness or injury, weather/climate and air pollution. Smoking is identified as the most widely studied non-occupational factor in occupational disease. Smoking interacts with some occupational exposures to produce more disease than the sum of both agents separately. Smoking and asbestos interact multiplicatively in lung cancer causation. The ability to quantify interactions between occupational and non-occupational factors in disease etiology is important in assessing priorities for preventive action. Despite this, only the interactions of smoking have begun to be defined. The many other non-occupational factors mentioned above have each been studied individually but their interactions with occupational factors have not been assessed. This report describes models of quantifying interactions and recommends that further work is carried out to assess the interactions of non-occupational factors other than smoking in disease causation.