Trude Eid Robsahm

Vitamin D3 from sunlight may improve the prognosis of breast-, colon- and prostate cancer (Norway)

Objective: To investigate whether prognosis of breast-, colon- and prostate cancer may be related to vitamin D3, induced from solar ultra-violet (UV) radiation, through studies on geographical and seasonal variations in UV radiation. Methods: This study includes 115,096 cases of breast-, colon- or prostate cancer, diagnosed between 1964 and 1992. Among these, 45,667 deaths due to the cancer were registered. On the basis of a north–south gradient in solar UV radiation and geographical climatic differences, Norway was divided into eight residential regions. According to seasonal variations in UV radiation, four periods of diagnosis during the year were used. Case fatality according to residential region and to season of diagnosis was estimated using Cox regression. The effects of occupational sun exposure, childbearing pattern and educational level were also evaluated. Results: No geographic variation in case fatality was observed for the three cancer types studied. A significant variation in prognosis by season of diagnosis was observed. Diagnoses during summer and fall, the seasons with the highest level of vitamin D3, revealed the lowest risk of cancer death. Conclusion: The results suggest that a high level of vitamin D3 at the time of diagnosis, and thus, during cancer treatment, may improve prognosis of the three cancer types studied.

Association between serum 25(OH)D and death from prostate cancer

Based on observations that for certain cancers, mortality varies according to sun exposure, vitamin D has been proposed to influence on disease progression. This study aims to investigate whether serum levels of 25(OH)D are associated with prognosis in patients with prostate cancer. In total, 160 patients with a serum sample in the JANUS serum bank were included. For 123 patients a pre-treatment serum sample was taken, whereas 37 of the patients had received hormone therapy prior to the blood collection. The serum level of 25(OH)D was classified as low (< 50 nmol l−1), medium (50–80 nmol l−1) or high (>80 nmol l−1). A Cox proportional hazard regression model was used to assess the association between serum 25(OH)D and cancer mortality. During follow-up, 61 deaths occurred, of whom 52 died of prostate cancer. The median time of follow-up was 44.0 months (range, 1.2–154.6). Serum 25(OH)D at medium or high levels were significantly related to better prognosis (RR 0.33; 95% CI 0.14–0.77, RR 0.16; 95% CI 0.05–0.43) compared with the low level. Analysis restricted to patients receiving hormone therapy gave a stronger association. The serum level of 25(OH)D may be involved in disease progression and is a potential marker of prognosis in patients with prostate cancer.

Body mass index, physical activity, and colorectal cancer by anatomical subsites: a systematic review and meta-analysis of cohort studies.

Several studies report varying incidence rates of cancer in subsites of the colorectum, as an increasing proportion appears to develop in the proximal colon. Varying incidence trends together with biological differences between the colorectal segments raise questions of whether lifestyle factors impact on the risk of cancer differently at colorectal subsites. We provide an updated overview of the risk of cancer at different colorectal subsites (proximal colon, distal colon, and rectum) according to BMI and physical activity to shed light on this issue. Cohort studies of colorectal cancer, published in English throughout 2010, were identified using PubMed. The risk estimates from 30 eligible studies were summarized for BMI and physical activity. A positive relationship was found between BMI and cancer for all colorectal subsites, but most pronounced for the distal colon [relative risk (RR) 1.59, 95% confidence interval (CI) 1.34–1.89]. For the proximal colon and rectum, the risk estimates were 1.24 (95% CI 1.08–1.42) and 1.23 (95% CI 1.02–1.48), respectively. Physical activity was related inversely to the risk of cancer at the proximal (RR 0.76, 95% CI 0.70-0.83) and distal colon (RR 0.77, 95% CI 0.71–0.83). Such a relationship could not be established for the rectum (RR 0.98, 95% CI 0.88–1.08). In conclusion, the results suggest minor differences in the associations of BMI and the risk of cancer between the colorectal subsites. For physical activity, the association does not seem to differ between the colonic subsites, but a difference was observed between the colon and the rectum, perhaps indicating that different mechanisms are operating in the development of colon and rectal cancer.

Season of diagnosis is a predictor of cancer survival. Sun-induced vitamin D may be involved : A possible role of sun-induced vitamin D

The calcidiol level in a group of Norwegians (14,000 individuals, age range 16-80) was found to be highest in late summer. The seasonal variation was larger for young than for old persons. The calcitriol concentration was practically constant throughout the year. Younger persons had less calcidiol and more calcitriol than older persons, indicating that the conversion of calcidiol to calcitriol is more efficient in younger persons. A seasonal variation of prognosis of cancer (colon-, breast-, prostate- cancer and Hodgkin lymphoma) was found. The survival is highest for summer and autumn diagnosis, corresponding to maximal calcidiol levels. Thus, calcidiol may act synergistically with traditional treatment modalities. In view of these calcitriol and calcidiol data, the seasonal variation of cancer survival may be related to the calcidiol gradient, indicating that this Vitamin D metabolite may be more important than believed so far.

Season of diagnosis is a prognostic factor in Hodgkin's lymphoma: a possible role of sun-induced vitamin D

Experimental studies show that vitamin D derivatives are potent anticarcinogenic factors. Epidemiological observations support this, and vitamin D sufficiency has been hypothesised to be an important risk-reducing factor in several forms of cancer. Vitamin D level exhibits seasonal variations. In the present work, we have investigated the effect of the season of diagnosis on the risk of death among Hodgkins lymphoma patients diagnosed in Norway between 1964 and 2000. Risk estimates were calculated as relative risk (RR), with 95% confidence intervals (95% CI), using Cox regression model. Epidemiological data for this period indicate that season of diagnosis is a strong prognostic factor for Hodgkins lymphoma, with ≈20% lower case fatality for patients diagnosed during autumn vs winter diagnosis (RR=0.783, 95% CI,−0.62 to 0.99; P=0.041). Notably, the improved autumnal survival rate was higher than 60% (RR=0.364, 95% CI, −0.15 to 0.87; P=0.025) for patients younger than 30 years. This finding may be related to higher endogenous levels of vitamin D in autumn, with a favourable influence on the conventional therapy.

Breast cancer incidence in food- vs non-food-producing areas in Norway: possible beneficial effects of World War II

It has been suggested that World War II influenced breast cancer risk among Norwegian women by affecting adolescent growth. Diet changed substantially during the war, and the reduction in energy intake was assumed to be larger in non-food- producing than in food-producing municipalities. In the present study, we have looked at the influence of residential history in areas with and without food production on the incidence of breast cancer in a population-based cohort study consisting of 597 906 women aged between 30 and 64 years. The study included 7311 cases of breast cancer, diagnosed between 1964 and 1992. The risk estimates were calculated using a Poisson regression model. The results suggest that residential history may influence the risk of breast cancer, where the suggested advantageous effect of World War II seems to be larger in non-food-producing than in food-producing areas. Breast cancer incidence was observed to decline for the post-war cohorts, which is discussed in relation to diet.

Breast and other cancers in 1445 blood relatives of 75 Nordic patients with ataxia telangiectasia

Epidemiological studies have consistently shown elevated rates of breast cancer among female blood relatives of patients with ataxia telangiectasia (AT), a rare autosomal recessive disease. A large proportion of the members of AT families are carriers of AT-causing gene mutations in ATM (Ataxia Telangiectasia Mutated), and it has been hypothesised that these otherwise healthy carriers are predisposed to breast cancer. This is an extended and enlarged follow-up study of cancer incidence in blood relatives of 75 patients with verified AT in 66 Nordic families. Blood relatives were identified through population registry linkages, and the occurrence of cancer was determined from cancer registry files in each country and compared with national incidence rates. The ATM mutation carrier probabilities of relatives were assigned from the combined information on location in family, consanguinity, if any, and supplementary carrier screening in some families. Among the 1445 blood relatives of AT patients, 225 cancers were observed, with 170.4 expected, yielding a standardised incidence ratio (SIR) of 1.3 (95% confidence interval (CI), 1.1–1.4). Invasive breast cancer occurred in 34 female relatives (SIR, 1.7; 95% CI, 1.2–2.4) and was diagnosed in 21 women before the age of 55 years (SIR, 2.9; 95% CI, 1.8–4.5), including seven mothers of probands (SIR, 8.1; 95% CI, 3.3–17). When the group of mothers was excluded, no clear relationship was observed between the allocated mutation carrier probability of each family member and the extent of breast cancer risk. We concluded that the increased risk for female breast cancer seen in 66 Nordic AT families appeared to be restricted to women under the age of 55 years and was due mainly to a very high risk in the group of mothers. The findings of breast cancer risk in mothers, but not other likely mutation carriers, in this and other studies raises questions about the hypothesis of a simple causal relationship with ATM heterozygosity.

Vitamin D, season, and risk of prostate cancer: a nested case-control study within Norwegian health studies

BACKGROUND It is biologically plausible that vitamin D might prevent prostate cancer. However, recent meta-analyses concluded that there is no consistent relation between circulating 25-hydroxyvitamin D [25(OH)D] concentrations and prostate cancer, and several large studies have actually reported an increased risk of prostate cancer associated with high 25(OH)D. OBJECTIVE We aimed to assess the prospective relations between serum 25(OH)D, serum retinol, and risk of prostate cancer. DESIGN In this nested case-control study, Norwegian men who participated in population-based health studies between 1981 and 1991 were followed with respect to prostate cancer throughout 2006. For each case (n = 2106), a matched control was selected. Stored serum was analyzed for 25(OH)D by using HPLC atmospheric pressure chemical ionization mass spectrometry. RESULTS We showed a positive relation between an increasing 25(OH)D concentration and prostate cancer risk [rate ratio (RR): 1.15 (95% CI: 1.04, 1.27) per 30-nmol/L increase in 25(OH)D concentration]. Predefined analyses stratified by season showed no relation for subjects with serum collected during winter and spring (RR: 1.00 per 30-nmol/L increase), whereas a strengthened positive association [RR: 1.27 (95% CI: 1.09, 1.47) per 30-nmol/L increase] was observed in men with serum collected during the summer and autumn. There was no relation between serum retinol and prostate cancer. CONCLUSIONS The cause for increased risk of prostate cancer related to a high 25(OH)D concentration only during the summer and autumn is not obvious. The effect may be related to vitamin D itself or to other factors associated with sun exposure.

Height, weight and gastrointestinal cancer: A follow-up study in Norway

It has been suggested that components of our diet play an essential role in carcinogenesis. Anthropometric indices, such as body weight and height, have often been considered as measurements of prevailing diet and nutrition in childhood respectively. To investigate to what extent height and body weight are associated with the risk of gastrointestinal cancer, data from a Norwegian screening programme for tuberculosis were analysed. More than 1,100,000 individuals, aged 30-69 years at the time of examination, were included in the study. Body weight, expressed as Quetelets index (QI), and height records were linked with vital status data from Statistics Norway and the Cancer Registry of Norway. The analysis shows that individuals in the first quintile of height had a lower relative risk than later quintiles for colon cancer, independent of sex and stage of disease at completion of follow-up. The association between height and rectal cancer is similar, but weaker. Men in the fifth quintile of QI have a relative risk of 1.39 for colon cancer, compared with the first quintile, and they also have a slightly elevated risk for rectal cancer. Among women, the pattern is unclear, but we observed a significant relationship between high QI and cancer of the gallbladder. Our results indicate that prevailing diet and living conditions in early life do play a role, and seem to support the hypothesis that anthropometric indices could be of importance as indirect markers for the risk of colon cancer and, to some extent, for cancer of the rectum and gallbladder.

Subsite-Specific Dietary Risk Factors for Colorectal Cancer: A Review of Cohort Studies

Objective. A shift in the total incidence from left- to right-sided colon cancer has been reported and raises the question as to whether lifestyle risk factors are responsible for the changing subsite distribution of colon cancer. The present study provides a review of the subsite-specific risk estimates for the dietary components presently regarded as convincing or probable risk factors for colorectal cancer: red meat, processed meat, fiber, garlic, milk, calcium, and alcohol. Methods. Studies were identified by searching PubMed through October 8, 2012 and by reviewing reference lists. Thirty-two prospective cohort studies are included, and the estimates are compared by sex for each risk factor. Results. For alcohol, there seems to be a stronger association with rectal cancer than with colon cancer, and for meat a somewhat stronger association with distal colon and rectal cancer, relative to proximal colon cancer. For fiber, milk, and calcium, there were only minor differences in relative risk across subsites. No statement could be given regarding garlic. Overall, many of the subsite-specific risk estimates were nonsignificant, irrespective of exposure. Conclusion. For some dietary components the associations with risk of cancer of the rectum and distal colon appear stronger than for proximal colon, but not for all.