A relationship between low back pain (LBP) and prolonged standing or prolonged sitting at work has not been clearly shown, despite its biological plausibility. Because sitting and standing postures vary as to duration and freedom to alternate postures, and standing postures vary as to mobility, associations between specific working postures and LBP were explored using multiple logistic regression. Associations between work factors and self-reported LBP during the previous 12 months that interfered with usual activities were examined among 4493 standing workers and 3237 sitting workers interviewed in the 1998 Quebec Health and Social Survey; 24.5% reported significant LBP. Since the same conditions can correspond to different physiological demands for sitting compared with standing workers, analyses were performed separately for the two groups. Standing without freedom to sit was associated with LBP. Different occupational physical and psychosocial factors were associated with LBP in sitting compared with standing populations.

More than twice as many workdays are lost to illness than for personal or family reasons. We examine possible workplace determinants of sickness absence among French workers in the food processing industry. These workers are exposed to a variety of environmental and organizational constraints: cold, uncomfortable postures, assembly-line work, and irregular schedules. In 1987-1988, a medical examination and questionnaire were administered to 558 men and 790 women as part of a study of 17 poultry slaughterhouses and 6 canning factories. Women's and men's working conditions were very different, and their sickness absences for musculoskeletal and respiratory illnesses were related to some of their specific working conditions: cold exposure, ill-adapted work stations, and problems with their supervisors and co-workers. If male and female workers were combined into a single analysis that adjusted for sex, many of the associations operant for a single sex could no longer be seen.

Working posture is an important determinant of musculoskeletal and vascular health. Knowledge of the context and type of postures is necessary in order to examine their associations with health-related outcomes. This study describes self-reported usual working postures in a population and their associations with other working conditions and demographic variables. The 1998 Quebec Health and Social Survey is a population-based survey of 11,986 private households in the province of Quebec. It contained a self-administered questionnaire, including an extensive occupational health section. The analyses in this study were limited to respondents with paid employment who had at least 6 months seniority in their current job, comprising 9,425 subjects. The overall prevalence of usual work in a standing posture is 58%; it is more common among men, workers under 25 years, those in the two lowest educational quintiles and those with incomes under 20,000 Canadian dollars. Only one person in six who works standing reports being able to sit at will. Women and men differ in the types of usual standing and sitting postures at work. Those who work standing and/or who work in more constrained postures are more likely to be exposed to other physical work demands, such as handling heavy loads, repetitive work, forceful exertion and low job decision latitude. The association between decision latitude and constrained postures is an important link between psychosocial and physical stressors in the workplace. In epidemiological studies, exposure covariation and interactions should be considered in the generation and interpretation of the associations between work postures and musculoskeletal disorders.

Perimenstrual symptoms are among the most common disorders of women. Seven perimenstrual symptoms were related to working conditions among 539 hospital workers in a retrospective cohort questionnaire study, as part of a larger examination of health problems and working conditions of Quebec hospital workers. Only 8% of women had experienced no symptoms of discomfort associated with their last menstrual period. Lower abdominal pain, the most common symptom (58% prevalence), was associated with lifting weights (usually patients) in a logistic regression adjusted for parity and contraceptive use. Back pain, leg pain, swelling, and headache were associated with indicators of time pressure and fast work speed. Back pain during menstruation was experienced by 44% of workers. Studies of the prevalence and etiology of back pain, a common occupational health problem among hospital workers, may be confused if perimenstrual back pain is not taken into account. Similar reservations hold for the results on other perimenstrual symptoms that are also likely to occur outside the perimenstrual period, such as leg pain, irritability, and headache.