Karen Messing

Studying the relationship between low back pain and working postures among those who stand and those who sit most of the working day.

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.

In vivo mutant frequency rises among breast cancer patients after exposure to high doses of γ-radiation

Human in vivo mutant frequencies can be measured by cloning freshly isolated lymphocytes in selective media containing 6-thioguanine (TG). This method was applied to monitoring environmental mutagenesis, by studying lymphocytes separated from peripheral blood of 12 cancer patients undergoing radiotherapy. Before therapy, cancer patients had an average 8.6 X 10(-6) mutants/cell, compared to 2.4 X 10(-6) mutants/cell for heart patients and 1.1 X 10(-6) mutants/cell for healthy controls. After exposure of cancer patients to 50 Gy of gamma-radiation delivered to the treated area, or an estimated 4 Gy received by each lymphocyte, patients averaged 36.8 X 10(-6) mutants/viable cell.

Sex as a variable can be a surrogate for some working conditions : Factors associated with sickness absence

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. Womens and mens 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.

Distal Lower-Extremity Pain and Work Postures in the Quebec Population

OBJECTIVES Standing at work has been associated with discomfort and cardiovascular symptoms. Because standing postures vary in duration, mobility, and constraint, we explored associations between specific postures and pain in the lower extremities. METHODS We used multiple logistic regression to analyze associations between work factors and pain in the lower extremities during the previous 12 months that interfered with usual activities. We used data from among 7757 workers who were interviewed in the 1998 Quebec Health and Social Survey. RESULTS Among all respondents, 9.4% reported significant ankle or foot pain, and 6.4% had lower-leg or calf pain. Significantly more women than men had pain at both sites. Both leg or calf and ankle or foot pain were strongly associated with standing postures, whole-body vibration, psychological distress, female gender, and being aged 50 years or older. Constrained standing postures were associated with increased ankle or foot pain for both men and women and with leg or calf pain for women, compared with standing with freedom to sit at will. CONCLUSIONS Freedom to sit at work may prevent lower-extremity pain. The effects of specific sitting and standing postures on cartilage, muscle, and the cardiovascular system may help explain discomfort in the lower extremities.

Standing, sitting and associated working conditions in the Quebec population in 1998

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 Québec. 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

First steps for integrating sex and gender considerations into basic experimental biomedical research

20,000 CAN. 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.

Mutant frequency of radiotherapy technicians appears to be associated with recent dose of ionizing radiation.

In recent decades there has been an increasing recognition of the need to account for sex and gender in biology and medicine, in order to develop a more comprehensive understanding of biological phenomena and to address gaps in medical knowledge that have arisen due to a generally masculine bias in research. We have noted that as basic experimental biomedical researchers, we face unique challenges to the incorporation of sex and gender in our work, and that these have remained largely unarticulated, misunderstood, and unaddressed in the literature. Here, we describe some of the specific challenges to the incorporation of sex and gender considerations in research involving cell cultures and laboratory animals. In our view, the main‐streaming of sex and gender considerations in basic biomedical research depends on an approach that will allow scientists to address these issues in ways that do not undermine our ability to pursue our fundamental scientific interests. To that end, we suggest a number of strategies that allow basic experimental researchers to feasibly and meaningfully take sex and gender into account in their work.—Ritz, S.A., Antle, D. M., Côté, J., Deroy, K., Fraleigh, N., Messing, K., Parent, L., St‐Pierre, J., Vaillancourt, C., Mergler, D. First steps for integrating sex and gender considerations into basic experimental biomedical research. FASEB J. 28, 4–13 (2014). www.fasebj.org

Can safety risks of blue-collar jobs be compared by gender?

The frequency of hypoxanthine phosphoribosyl transferase (HPRT) mutants among peripheral T-lymphocytes of radiotherapy technicians primarily exposed to 60Co was measured by the T-cell cloning method. Mutant frequencies of these technicians in 1984 and 1986 were significantly higher than those of physiotherapy technicians who worked in a neighboring service, and correlated significantly with thermoluminescence dosimeter readings recorded during the 6 mo preceding mutant frequency determination. Correlations decreased when related to dose recorded over longer time intervals. HPRT mutant frequency determination in peripheral lymphocytes is a good measure of recently received biologically effective radiation dose in an occupationally exposed population.

The aprt heterozygote/hemizygote system for screening mutagenic agents allows detection of large deletions

Studies of accident rates use denominators which vary in their precision and detail. These imprecisions may impact differentially on accident rates of men and women, given their distribution across the labour market. Difficulties in making male/female comparisons were illustrated by a study of accidents and health symptoms among blue collar workers. We examined occupational health claims presented to the Quebec Occupational Health and Safety Commission by male and female municipal workers in 1989–1990, and interviewed 55 male and 58 female workers, asking questions on health symptoms and difficulties experienced on the job. No increase in accidents was found among permanent women workers compared with their male equivalents, and precipitating events and sites of injury were similar. However, the statistics were not strictly comparable. Four factors complexified the male-female comparisons of accident rates: (1) gender differences in hours worked, (2) gendered task assignments within industrial classifications, occupations and job titles, (3) gender differences in age/seniority, and (4) gender differences in the interaction between equipment and tool dimensions and work activity. Women were less senior, worked fewer hours and were assigned to a small minority of job titles. Interviews revealed a gendered division of labour within many supposedly integrated jobs, and use of different methods to do the same tasks. Men and women reported different musculoskeletal symptom profiles, which could be attributed to differences in tasks, biology or work methods. In view of these results, we suggest that comparing male and female accident rates be done with extreme prudence, taking into account womens and mens specific situations in the workplace.

Are Women in Female Jobs for Their Health? A Study of Working Conditions and Health Effects in the Fish-Processing Industry in Quebec:

Frequencies of mutation at the hprt and aprt loci in various CHO cell lines were measured after exposure of the cells to ionizing radiation. In D423 and AA8-16, which are aprt+/- heterozygotes, the ratio of hprt- mutants to aprt- mutants ranged from 0.11 to 0.36. In D422 and AA8-5, which are aprt+/0 cell lines in which only one copy of the gene and its flanking sequences is present these ratios were greater than 5. In contrast, chemical mutagenesis generated mutations at both loci, in all cell lines, at equal frequencies. Southern blot analysis of DNA from hprt- and aprt- mutants of one of the aprt+/- heterozygous lines showed some apparently unaltered genes, some rearrangements and some complete deletions of hprt among hprt- mutants, but only complete deletions of aprt-linked sequences among aprt- mutants. These results strongly suggest that X-ray-induced mutational events are frequently larger than 40 kb (the length of the hprt gene) and that the difference among the frequencies observed at the two loci in the two types of cell lines were due to the presence of essential sequences close the respective target genes. The combined use of these cell lines in screening environmental mutagens should allow qualitative as well as quantitative analysis of the mutagenic potential of environmental agents.