Occupation and mammographic density: A population-based study (DDM-Occup).

INTRODUCTION: High mammographic density is one of the main risk factors for breast cancer. Although several occupations have been associated with breast cancer, there are no previous occupational studies exploring the association with mammographic density. Our objective was to identify occupations associated with high mammographic density in Spanish female workers. METHODS: We conducted a population-based cross-sectional study of occupational determinants of high mammographic density in Spain, based on 1476 women, aged 45-68 years, recruited from seven screening centers within the Spanish Breast Cancer Screening Program network. Reproductive, family, personal, and occupational history data were collected. The latest occupation of each woman was collected and coded according to the 1994 National Classification of Occupations. Mammographic density was assessed from the cranio-caudal mammogram of the left breast using a semi-automated computer-assisted tool. Association between mammographic density and occupation was evaluated by using mixed linear regression models, using log-transformed percentage of mammographic density as dependent variable. Models were adjusted for age, body mass index, menopausal status, parity, smoking, alcohol intake, educational level, type of mammography, first-degree relative with breast cancer, and hormonal replacement therapy use. Screening center and professional reader were included as random effects terms. RESULTS: Mammographic density was higher, although non-statistically significant, among secondary school teachers (eß = 1.41; 95%CI = 0.98-2.03) and nurses (eß = 1.23; 95%CI = 0.96-1.59), whereas workers engaged in the care of people (eß = 0.81; 95%CI = 0.66-1.00) and housewives (eß = 0.87; 95%CI = 0.79-0.95) showed an inverse association with mammographic density. A positive trend for every 5 years working as secondary school teachers was also detected (p-value = 0.035). CONCLUSIONS: Nurses and secondary school teachers were the occupations with the highest mammographic density in our study, showing the latter a positive trend with duration of employment. Future studies are necessary to confirm if these results are due to chance or are the result of a true association whose causal hypothesis is, for the moment, unknown.

[Exposure to ergonomic risk by occupation in Spanish working: a data exploitation of MatEmESp]. / Exposición a carga física en el trabajo por ocupación: una explotación de los datos en matriz empleo-exposición Española (MATEMESP).

BACKGROUND: Ergonomic hazards exposure is the main cause of occupational pain. The aim of this paper is to describe the prevalence of exposure to occupational physical load by occupation, in Spanish working population, and its relationship to employment conditions and sociodemographic characteristics of workers. METHODS: We used the information contained in the Spanish Job-Exposure Matrix (MatEmESp), with data between 1997 and 2005. We describe the prevalence of exposure to ergonomic hazards, we identify the occupations with the highest prevalence of exposure and we analyze its relationship to employment conditions and sociodemographic characteristics by occupation, using Spearman correlation coefficients and Scatter plots. RESULTS: Repetitive movements are ergonomic hazard most frequently reported (prevalence around 60%). The greater prevalence of exposure to awkward postures are given in "Bricklayers" (96%), to handling loads in "construction labourers" (89%), to repetitive movements in "graphic arts workers" (95%) and sedentary work in "administrative assistants" (98%). We found a strong relationship (p<0,001) between the prevalence of exposure to the four hazards considered, and the proportion of people with primary education by occupation (correlation coefficients -0,62 in sedentary work and between 0,59 and 0,66 in the other). Occupations with a high proportion of women and with a university studies levels ("nurses"), also has frequent exposure to handling loads (>50%). CONCLUSIONS: In general, the prevalence of exposure to ergonomic hazards remains high in the period analyzed. Less qualified occupations usually have a higher prevalence of exposure.