CYP17 promoter polymorphism and breast cancer risk in males and females in relation to BRCA2 status

A T-C polymorphism in the promoter region of the CYP17 gene has been associated with male and female breast cancer risk as well as early-onset familial breast cancer. The potential role of this polymorphism was investigated in relation to breast cancer risk in Icelandic male and female carriers and noncarriers of a BRCA2 mutation. The study population consisted of 39 male and 523 female breast cancer cases and 309 male and 395 female controls. Of the cases, 15 males and 55 females carried a BRCA2 mutation. We did not find a significant association between male breast cancer risk and CYP17 genotypes. Among male breast cancer cases, the frequency of the CC genotype was higher among carriers of the 999del5 mutation (33.3%) than noncarriers (16.7%), although this difference also did not reach a statistical significance. No association was observed with breast cancer risk among females irrespective of menopausal status, stage of the disease or BRCA2 status. Our findings do not indicate a role for the CYP17 T-C polymorphism in female breast cancer, but a role in male carriers of a BRCA2 mutation could not be excluded because of the small sample size.     

Effects of occupation on risks of avoidable cancers in the Nordic countries

Knowledge of cancer risk according to occupational affiliation is an essential part of formatting preventive actions aimed at the adult population. Herein, data on 10 major cancer sites amenable by life style exposures from the Nordic Occupational Cancer Study (NOCCA) are presented. All subjects aged 30–64 years participating in one or more national censuses in Denmark, Finland, Iceland, Norway, or Sweden between 1960 and 1990 were included in the cohort and followed up for cancer from inclusion until 2003/2005 via a linkage with the national cancer registries, and standardised incidence ratios (SIRs) were computed. Variation in risk across occupations was generally larger in men than in women. In men, the most consistent cluster with high risk of numerous cancer types included waiters, cooks and stewards, beverage workers, seamen, and chimney sweeps. Two clusters of occupations with generally low cancer risks were seen in both men and women. The first one comprised farmers, gardeners, and forestry workers, the second one included groups with high education, specifically those in health and pedagogical work. Although cancer risk varies by occupation, only a smaller part of the variation can be attributed to occupational exposures in the strict sense. Preventive measures at the work place are important to avoid established and new occupational health hazards. This study also indicates that the work place in addition should be seen as a useful arena for reaching groups of adults with more or less similar habits and attitudes for general health promotion.     

Development of a dietary screening questionnaire to predict excessive weight gain in pregnancy

Excessive gestational weight gain (GWG) is a risk factor for several adverse pregnancy outcomes, including macrosomia. Diet is one of the few modifiable risk factors identified. However, most dietary assessment methods are impractical for use in maternal care. This study evaluated whether a short dietary screening questionnaire could be used as a predictor of excessive GWG in a cohort of Icelandic women. The dietary data were collected in gestational weeks 11–14, using a 40‐item food frequency screening questionnaire. The dietary data were transformed into 13 predefined dietary risk factors for an inadequate diet. Stepwise backward elimination was used to identify a reduced set of factors that best predicted excessive GWG. This set of variables was then used to calculate a combined dietary risk score (range 0–5). Information regarding outcomes, GWG (n = 1,326) and birth weight (n = 1,651), was extracted from maternal hospital records. In total, 36% had excessive GWG (Icelandic criteria), and 5% of infants were macrosomic (≥4,500 g). A high dietary risk score (characterized by a nonvaried diet, nonadequate frequency of consumption of fruits/vegetables, dairy, and whole grain intake, and excessive intake of sugar/artificially sweetened beverages and dairy) was associated with a higher risk of excessive GWG. Women with a high (≥4) versus low (≤2) risk score had higher risk of excessive GWG (relative risk = 1.23, 95% confidence interval, CI [1.002, 1.50]) and higher odds of delivering a macrosomic offspring (odds ratio = 2.20, 95% CI [1.14, 4.25]). The results indicate that asking simple questions about women's dietary intake early in pregnancy could identify women who should be prioritized for further dietary counselling and support.     

Relationship between serum parathyroid hormone levels, vitamin D sufficiency, and calcium intake

Context  Adequate vitamin D status for optimum bone health has received increased recognition in recent years; however, the ideal intake is not known. Serum 25-hydroxyvitamin D is the generally accepted indicator of vitamin D status, but no universal reference level has been reached. Objective  To investigate the relative importance of high calcium intake and serum 25-hydroxyvitamin D for calcium homeostasis, as determined by serum intact parathyroid hormone (PTH). Design, Setting, and Participants  Cross-sectional study of 2310 healthy Icelandic adults who were divided equally into 3 age groups (30-45 years, 50-65 years, or 70-85 years) and recruited from February 2001 to January 2003. They were administered a semi-quantitative food frequency questionnaire, which assessed vitamin D and calcium intake. Participants were further divided into groups according to calcium intake (<800 mg/d, 800-1200 mg/d, and >1200 mg/d) and serum 25-hydroxyvitamin D level (<10 ng/mL, 10-18 ng/mL, and >18 ng/mL). Main Outcome Measure  Serum intact PTH as determined by calcium intake and vitamin D. Results  A total of 944 healthy participants completed all parts of the study. After adjusting for relevant factors, serum PTH was lowest in the group with a serum 25-hydroxyvitamin D level of more than 18 ng/mL but highest in the group with a serum 25-hydroxyvitamin D level of less than 10 ng/mL. At the low serum 25-hydroxyvitamin D level (<10 ng/mL), calcium intake of less than 800 mg/d vs more than 1200 mg/d was significantly associated with higher serum PTH (P = .04); and at a calcium intake of more than 1200 mg/d, there was a significant difference between the lowest and highest vitamin D groups (P = .04). Conclusions  As long as vitamin D status is ensured, calcium intake levels of more than 800 mg/d may be unnecessary for maintaining calcium metabolism. Vitamin D supplements are necessary for adequate vitamin D status in northern climates.      

Serum 25-Hydroxy-Vitamin D Status and Incident Hip Fractures in Elderly Adults: Looking Beyond Bone Mineral Density

Observational studies have consistently reported a higher risk of fractures among those with low levels of serum 25-hydroxyvitamin D (25(OH)D). Emerging evidence suggests that low serum 25(OH)D levels may increase the rate of falls through impaired physical function. Examine to what extent baseline measures of volumetric bone mineral density (vBMD), absolute bone mineral content (BMC), and markers of physical function may explain incident hip fractures in older adults with different serum levels of 25(OH)D. A prospective study of 4309 subjects (≥66 years) recruited between 2002 and 2006 into the Age, Gene/Environment Susceptibility-Reykjavik (AGES-Reykjavik) study. Hip fractures occurring until the end of 2012 were extracted from hospital records. Prevalence of serum 25(OH)D deficiency (<30 nmol/L), inadequacy (30–<50 nmol/L), and sufficiency (≥50 nmol/L) was 6%, 23%, and 71% for males; and 11%, 28%, and 53% for females, respectively. Female participants had ~30% lower absolute BMC compared to males. Serum 25(OH)D concentrations were positively associated with vBMD and BMC of the femoral neck and markers of physical function, including leg strength and balance. Those who had deficient compared to sufficient status at baseline had a higher age-adjusted risk of incidence hipfractures with hazard ratios (HRs) of 3.1 (95% confidence interval [CI], 1.9–5.2) and 1.8 (95% CI, 1.3–2.5) among males and females, respectively. When adjusting for vBMD and measures of physical function, the association was attenuated and became nonsignificant for males (1.3; 95% CI, 0.6–2.5) but remained significant for females (1.7; 95% CI, 1.1–2.4). Deficient compared to sufficient serum 25(OH)D status was associated with a higher risk of incident hip fractures. This association was explained by poorer vBMD and physical function for males but to a lesser extent for females. Lower absolute BMC among females due to smaller bone volume may account for these sex-specific differences. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Occupational exposure to wood dust and risk of nasal and nasopharyngeal cancer: A case‐control study among men in four nordic countries—With an emphasis on nasal adenocarcinoma

The current study aims to provide stronger evidence to aid in our understanding of the role of cumulative occupational exposure to (softwood‐dominated) mixed wood dust in aetiology of nasal cancer. We included broad exposure occurred in a range of wood‐processing occupation across varied industries in four Nordic countries. A population‐based case‐control study was conducted on all male cases with nasal adenocarcinoma (393 cases), other types of nasal cancer (2,446) and nasopharyngeal cancer (1,747) diagnosed in Finland, Sweden, Norway and Iceland between 1961 and 2005. For each case, five male controls, who were alive at the time of diagnosis of the case (index date), were randomly selected, matched by birth‐year and country. Cumulative exposures (CE)s to wood dust and formaldehyde before the index date were quantified based on a job‐exposure matrix linked to occupational titles derived from population censuses. Hazard ratios (HRs) for the CE of wood dust were estimated by conditional logistic regression, adjusted for CE to formaldehyde and 95% confidence intervals (CIs) were calculated. There was an increasing risk of nasal adenocarcinoma related to wood dust exposure. The HR in the highest CE category of wood dust (≥ 28.82 mg/m³‐years) was 16.5 (95% CI 5.05–54.1). Neither nonadenocarcinoma of the nose nor nasopharyngeal cancer could be linked to wood dust exposure. CE to softwood‐dominated mixed wood dusts is strongly linked with elevated risk in nasal adenocarcinoma but not with other types of nasal or nasopharyngeal cancer.