Sun exposure and non-Hodgkin lymphoma

Etiology of non-Hodgkin lymphoma: A review from epidemiologic studies

Non-Hodgkin lymphoma (NHL) contributes to significant cancer burden and mortality globally. In recent years, much insight into the causes of NHL has been gained by evaluating global differences through international collaboration and data pooling. NHL comprises different subtypes that are known to behave differently, exhibit different prognoses, and start in distinct cell types (B-cell, T-cell, and NK-cell, predominantly), and there is increasing evidence that NHL subtypes have different etiologies. Classification of NHL can be complex, with varying subtype frequencies, and is a consideration when evaluating geographic differences. Because of this, international pooling of well-executed epidemiologic studies has conferred power to evaluate NHL by subtype and confidence with minimal misclassification. Given the decreasing burden in some regions while cases rise in Asia, and especially China, this report focuses on a review of the established etiology of NHL from the epidemiologic literature in recent decades, highlighting work from China. Topics covered include demographic patterns and genetic determinants including family history of NHL, as well as infection and immunosuppression, lifestyle, environment, and certain occupational exposures contributing to increased disease risk.

Significant current epidemiological trend: Haematological malignancies as subsequent primary tumours in cancer patients

BACKGROUND

Numbers of patients who develop subsequent primary tumours have markedly increased recently. This study aimed to carry out a comprehensive analysis documenting the risk of incidence of subsequent haematological malignancies.

METHODS

The Czech National Cancer Registry was the main data source, containing records of 126,822 haematological malignancies diagnosed in the period 1977-2016. Subsequent haematological malignancies were identified according to IACR rules. Joinpoint regression was employed to assess the time trends. The risk of development of subsequent haematological malignancy was evaluated by the standardised incidence ratio. The Kaplan-Meier curves were used to assess the differences in survival.

RESULTS

Age-standardised incidence of subsequent haematological malignancies increased from 0.5 in 1977 to 9.1 in 2016. In 1992, there was a significant change in the trend: a sharp increase by 7.7 % annually was revealed thereafter. The risk of development of a haematological malignancy was approximately 1.5 times higher in persons with history of any cancer than in the general Czech population. Patients with haematological malignancies - mainly myelodysplastic syndromes, polycythaemia vera and non-Hodgkin lymphoma - were shown to be at the highest risk of developing a subsequent haematological malignancy. While the median survival following a first haematological malignancy was 2.3 years, it was only 1.1 years for subsequent haematological malignancies (p < 0.001).

CONCLUSIONS

Our study identified the highest-risk diagnoses in terms of development of subsequent haematological malignancy. The results might be useful to set up correctly follow-up procedures from which cancer patients could benefit.

Does sunlight protect us from cancer?

The Ultraviolet (UV) radiation contained in sunlight is a powerful mutagen and immune suppressant which partly explains why exposure to solar UV is the biggest risk factor for the development of cutaneous tumours. Evidence is building that sunlight may be protective against some internal malignancies. Because patients with these tumours are often vitamin D deficient, this has led some to propose that vitamin D supplementation will be beneficial in the treatment of these cancers. However, the results from already completed trials have been disappointing which has given weight to the argument that there must be something else about sunlight that explains its cancer-protecting properties.

Complementary and Integrative Medicine in Hematologic Malignancies: Questions and Challenges

Hematologic malignancies represent 9.7% of all cancers, making them the fourth most common type of cancer in the United States. The aggressive and complex treatments administered in hematologic malignancies result in a high burden of psychological needs. Complementary and integrative medicine (CIM) is becoming one of the options that patients use to address their distress during and after cancer treatments. It is not clear whether appropriate CIM can relieve distress in patients affected by these malignancies. This review covers the potential benefits of CIM as relates to nutrition, nutritional supplements, exercise, circadian rhythm, methods for reducing distress during bone marrow aspiration, massage therapy, and acupuncture, in treating patients with hematological malignancies. This review may provide a framework to enhance patient-doctor dialogue regarding CIM use in hematologic malignancies.

Meat intake and non-Hodgkin lymphoma: a meta-analysis of observational studies

PURPOSE

High intake of meat has been inconsistently associated with increased risk of non-Hodgkin lymphoma (NHL). We carried out a meta-analysis to summarize the evidence of published observational studies reporting association between red meat and processed meat intake and NHL risk.

METHODS

Analytical studies reporting relative risks with 95 % confidence intervals (95 % CI) for the association between intake of red and/or processed meat and NHL or major histological subtypes were eligible. We conducted random-effects meta-analysis comparing lowest and highest intake categories and dose-response meta-analysis when risk estimates and intake levels were available for more than three exposure classes.

RESULTS

Fourteen studies (four cohort and ten case-control) were included in the meta-analysis, involving a total of 10,121 NHL cases. The overall relative risks of NHL for the highest versus the lowest category of consumption were 1.14 (95 % CI 1.03, 1.26) for red meat and 1.06 (95 % CI 0.98, 1.15) for processed meat. Significant associations were present when the analysis was restricted to case-control studies but not when restricted to cohort studies. No significant associations were found for major NHL etiological subtypes. Dose-response meta-analysis could be based only on eight studies that provided sufficient data, and compared to no meat consumption, the overall NHL relative risk increased nonlinearly with increased daily intake of red meat.

CONCLUSION

The observed positive association between red meat consumption and NHL is mainly supported by the effect estimates coming from case-control studies and is affected by multiple sources of heterogeneity. This meta-analysis provided mixed and inconclusive evidences on the supposed relationship between red and processed meat consumption and NHL.

Melanoma in patients with chronic lymphocytic leukemia and non-Hodgkin lymphoma

BACKGROUND

The relationship between melanoma and chronic lymphocytic leukemia (CLL) or non-Hodgkin lymphoma (NHL) has been minimally investigated.

OBJECTIVE

The objective of this study was to examine the incidence of melanoma in patients with a history of CLL or NHL, and their associated mortality.

METHODS

Cohorts of Kaiser Permanente Southern California members with a history of CLL and NHL were identified. Age-adjusted incidence density rates of melanoma among patients with CLL or NHL were compared with rates of melanoma among the general population of Kaiser Permanente Southern California patients. The mortality of patients with melanoma was examined using Cox proportional hazards modeling.

RESULTS

The age-adjusted incidence rate per 100,000 person-years for melanoma among patients with either CLL or NHL was 107 (95% confidence interval 84.4-129.6) versus 25.9 among the general population (95% confidence interval 84.4-129.6, P < .001). Patients with melanoma and a history of CLL or NHL had 2.46 greater odds of death compared with those without CLL or NHL (95% confidence interval 1.77-3.41).

LIMITATIONS

This study was retrospective in nature; the International Classification of Diseases, Ninth Revision codes used may contain diagnostic errors; and only overall survival was used in our analysis.

CONCLUSIONS

Patients with a history of CLL or NHL have a higher incidence of melanoma. Patients with CLL or NHL who are subsequently given the diagnosis of melanoma have a higher mortality than patients with melanoma without a preceding diagnosis of CLL.

Cancer incidence in southwest of iran: first report from khuzestan population-based cancer registry, 2002-2009

BACKGROUND

Cancer incidence rates are increasing particularly in developing countries. It is crucial for policy makers to know basic cancer epidemiology in each region to design comprehensive prevention plans. There have hitherto been no population-based data available for cancer in Khuzestan province. The present report is a first from the regional population-based cancer registry for the period of 2002-2009.

MATERIALS AND METHODS

Data were collected retrospectively reviewing all new cancer patients whom were registered in Khuzestan province cancer registry during an 8-year period (2002-2009). All cases were coded based on the ICD-O-3 coding system and collected data were computerized using SPSS (Chicago, IL) software, version 11.5. The age standardized incidence rates (ASRs) per 100,000 person-year for all cancers were computed using the indirect method of standardization to the world population.

RESULTS

During the 8-year study period, 16,801 new cancer cases were registered. Based on the computed ASRs, the five most frequent malignancies in females were breast (26.4 per 100,000), skin (13.6), colorectal (5.72), stomach (4.31) and bladder(4.07) and in males, the five most frequent were skin (16.0 per 100,000), bladder (10.7),prostate (7.64), stomach (7.17), and colorectal (6.32).The ASR for all malignancies in women was 92.5 per 100,000, and that for men was 87.4.

CONCLUSIONS

The observed patterns from the analysis of Khuzestan cancer registry data will lead to better understanding of the epidemiology of various malignancies in this part ofthe country and consequently provide a useful guide for authorities to make efficacious decisions and policies about a cancer control program for south-west Iran.

Plasma 25-hydroxyvitamin D concentration and lymphoma risk: results of the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

The relation between vitamin D status and lymphoma risk is inconclusive.

OBJECTIVE

We examined the association between prediagnostic plasma 25-hydroxyvitamin D [25(OH)D] and lymphoid cancer risk.

DESIGN

We conducted a study nested within the European Prospective Investigation into Cancer and Nutrition cohort of 1127 lymphoma cases and 1127 matched controls with a mean follow-up time of 7.1 y. Conditional logistic regression was used to estimate multivariable-adjusted incidence rate ratios of lymphoma risk in relation to plasma 25(OH)D. Season-standardized and season-specific 25(OH)D quartiles were used. We also analyzed 25(OH)D as a continuous variable and used predefined cutoffs.

RESULTS

No statistically significant association between plasma 25(OH)D and overall lymphoid cancer risk was observed. A positive association for B-cell non-Hodgkin lymphoma was noted only in those with a diagnosis made during the first 2 y of follow-up (P-heterogeneity = 0.03), which suggests the possibility of reverse causality. Further analysis restricted to participants with ≥2 y of follow-up time showed a significant association between 25(OH)D and chronic lymphocytic leukemia (CLL) (n = 161): adjusted incidence rate ratios were 0.40 (95% CI: 0.18, 0.90; P-trend = 0.05) and 0.31 (95% CI: 0.13, 0.76; P-trend = 0.03) for the top compared with the bottom season-standardized and season-specific quartiles, respectively. Data on dietary vitamin D intake provided further support for the observed association (incidence rate ratio: 0.33; 95% CI = 0.12, 0.89; P-trend = 0.006).

CONCLUSIONS

Our findings do not support a protective role of high 25(OH)D concentration in lymphoid cancers overall. However, they suggest that higher concentrations of 25(OH)D are associated with a reduced risk of CLL.

Latitude gradients for lymphoid neoplasm subtypes in Australia support an association with ultraviolet radiation exposure

Given the uncertainty surrounding solar ultraviolet radiation (UVR) exposure and risk of lymphoid neoplasms, we performed an ecological analysis of national Australian data for incident cases diagnosed between 2002 and 2006. Subtype-specific incidence was examined by latitude band (<29°S, 29-36°S, ≥37°S), a proxy for ambient UVR exposure, using multiple Poisson regression, adjusted for sex, age-group and calendar year. Incidence increased with distance from the equator for several mature B-cell non-Hodgkin lymphomas, including diffuse large B-cell [incidence rate ratio (IRR) = 1.37; 95% confidence interval (CI): 1.16-1.61 for latitude ≥37°S relative to <29°S], lymphoplasmacytic (IRR = 1.34; 95% CI: 1.12-1.61), mucosa-associated lymphoid tissue (IRR = 1.32; 95% CI: 0.97-1.80) and mantle cell lymphoma (IRR = 1.29; 95% CI: 1.05-1.58), as well as plasmacytoma (IRR = 1.52; 95% CI: 1.09-2.11) and plasma cell myeloma (IRR = 1.15; 95% CI: 1.03-1.27). A similar pattern was observed for several mature cutaneous T-cell neoplasms, including primary cutaneous anaplastic large cell lymphoma (IRR = 4.26; 95% CI: 1.85-9.84), mycosis fungoides/Sézary syndrome (IRR = 1.72; 95% CI: 1.20-2.46), and peripheral T-cell lymphoma not otherwise specified (NOS) (IRR = 1.53; 95% CI: 1.17-2.00). Incidence of mixed cellularity/lymphocyte-depleted (IRR = 1.60; 95% CI: 1.16-2.20) and nodular sclerosis Hodgkin lymphoma (IRR = 1.57; 95% CI: 1.33-1.85) also increased with distance from the equator. Many of these subtypes have a known association with infection or immune dysregulation. Our findings support a possible protective effect of UVR exposure on the risk of several lymphoid neoplasms, possibly through vitamin D-related immune modulation critical in lymphomagenesis.

Geographic distribution of hematopoietic cancers in the Nile delta of Egypt

BACKGROUND

Previous evidence indicated that incidence rates of non-Hodgkin's lymphoma (NHL) are high in Egypt although little is known about risk factors.

MATERIALS AND METHODS

Using data from the population-based cancer registry of Gharbiah governorate in Egypt, we assessed the 1999-2005 incidence of hematopoietic cancers (HCs) based on the ICD-O3 by age- and sex-specific urban-rural distribution.

RESULTS

NHL showed the highest incidence among all HCs (11.7 per 100 000). Urban incidence of HCs was higher than rural incidence. Incidence rates of Hodgkin's lymphoma (HL) and NHL were high especially among urban males up to the 64-year age category. Rural incidence of HL and NHL was high below age 20. Among the districts of the governorate, we observed NHL incidence pattern similar to that observed for hepatocellular carcinoma because of the possible link to hepatitis C virus for both cancers. Comparison to the published HCs data from Algeria, Cyprus, and Jordan showed the highest NHL rate in Egypt than the other countries in the region.

CONCLUSIONS

Future studies should define the role of environmental exposures in hematopoietic carcinogenesis in this population. In-depth studies should also investigate the role of access to health care in the urban-rural variation of HC distribution in this population.

Prospective study of ultraviolet radiation exposure and risk of cancer in the United States

Ecologic studies have reported that solar ultraviolet radiation (UVR) exposure is associated with cancer; however, little evidence is available from prospective studies. We aimed to assess the association between an objective measure of ambient UVR exposure and risk of total and site-specific cancer in a large, regionally diverse cohort [450,934 white, non-Hispanic subjects (50-71 years) in the prospective National Institutes of Health (NIH)-AARP Diet and Health Study] after accounting for individual-level confounding risk factors. Estimated erythemal UVR exposure from satellite Total Ozone Mapping Spectrometer (TOMS) data from NASA was linked to the US Census Bureau 2000 census tract (centroid) of baseline residence for each subject. We used Cox proportional hazards models adjusted for multiple potential confounders to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for quartiles of UVR exposure. Restricted cubic splines examined nonlinear relationships. Over 9 years of follow-up, UVR exposure was inversely associated with total cancer risk (N = 75,917; highest versus lowest quartile; HR = 0.97, 95% CI = 0.95-0.99; p-trend < 0.001). In site-specific cancer analyses, UVR exposure was associated with increased melanoma risk (highest versus lowest quartile; HR = 1.22, 95% CI = 1.13-1.32; p-trend < 0.001) and decreased risk of non-Hodgkin's lymphoma (HR = 0.82, 95% CI = 0.74-0.92) and colon (HR = 0.88, 95% CI = 0.82-0.96), squamous cell lung (HR = 0.86, 95% CI = 0.75-0.98), pleural (HR = 0.57, 95% CI = 0.38-0.84), prostate (HR = 0.91, 95% CI = 0.88-0.95), kidney (HR = 0.83, 95% CI = 0.73-0.94) and bladder (HR = 0.88, 95% CI = 0.81-0.96) cancers (all p-trend < 0.05). We also found nonlinear associations for some cancer sites, including the thyroid and pancreas. Our results add to mounting evidence for the influential role of UVR exposure on cancer.

Prognostic impact of serum 25-hydroxivitamin D [25(OH)D] concentrations in patients with lymphoid malignancies

The incidence of lymphoid malignancies has been increasing rapidly. Despite growing evidence for a relationship between serum 25-hydroxivitamin D [25(OH)D] concentrations and solid tumor risk, far less is known about the relationship between 25(OH)D and the risk of hematologic malignancy. This study aimed to assess the prognostic relevance of serum 25(OH)D concentrations in patients with B chronic lymphocytic leukemia (B-CLL) and non Hodgkin's lymphoma (NHL). The study was carried out on 195 newly diagnosed patients (75 B-CLL and 120 NHL) as well as 30 normal healthy controls. For all patients and normal controls serum 25(OH)D concentrations were assayed by enzyme-linked immunosorbent assay. Serum 25(OH)D levels were significantly lower in B-CLL and NHL patients as compared with normal controls (P = 0.00 for both). Also, there are significant associations between serum 25(OH)D levels and positive CD 38, positive ZAP 70 as well as Binet stages (χ(2) = 16.071, 16.644, 21.134 respectively; P = 0.00 for all) in the B-CLL patient group. Moreover, there are significant associations between serum 25(OH)D status and international prognostic index (IPI), performance status (χ(2) = 6.994, 9.212, P = 0.02, 0.01 respectively), but not with clinical stages (χ(2) = 3.115, P = 0.539) in NHL. Multivariate analysis revealed that 25(OH)D insufficiency is an independent poor prognostic factor in both B-CLL and NHL patient groups. In conclusion, 25(OH)D insufficiency is an independent poor prognostic factor in patients with B-CLL and NHL. 25(OH)D might be a therapeutic target in lymphoid malignancies.

Current understanding of lifestyle and environmental factors and risk of non-hodgkin lymphoma: an epidemiological update

The incidence rates of non-Hodgkin lymphoma (NHL) have steadily increased over the last several decades in the United States, and the temporal trends in incidence can only be partially explained by the HIV epidemic. In 1992, an international workshop sponsored by the United States National Cancer Institute concluded that there was an “emerging epidemic” of NHL and emphasized the need to investigate the factors responsible for the increasing incidence of this disease. Over the past two decades, numerous epidemiological studies have examined the risk factors for NHL, particularly for putative environmental and lifestyle risk factors, and international consortia have been established in order to investigate rare exposures and NHL subtype-specific associations. While few consistent risk factors for NHL aside from immunosuppression and certain infectious agents have emerged, suggestive associations with several lifestyle and environmental factors have been reported in epidemiologic studies. Further, increasing evidence has suggested that the effects of these and other exposures may be limited to or stronger for particular NHL subtypes. This paper examines the progress that has been made over the last twenty years in elucidating the etiology of NHL, with a primary emphasis on lifestyle factors and environmental exposures.

Intake of vitamins D and A and calcium and risk of non-Hodgkin lymphoma: San Francisco Bay Area population-based case-control study

Several nutrients identified as potentially cancer protective have been inconsistently associated with non-Hodgkin lymphoma (NHL) risk. Dietary history data, including use of vitamin supplements, were collected using a semiquantitative food frequency questionnaire administered during in-person interviews with 4,133 participants (2,052 cases, 2,081 controls) in a San Francisco Bay Area population-based case-control study. Data were used to determine the association of intake levels of vitamins D and A and calcium with risk of NHL and NHL subtypes. Odds ratios (OR) and 95% confidence intervals (CI) were computed as estimates of relative risk using adjusted unconditional logistic regression. Increasing vitamin D intake from food and supplements was positively associated with NHL risk in men (5th quintile: OR = 1.6, 95% CI = 1.0-2.4, P(trend) = 0.07) and with diffuse large B-cell lymphoma (DLBCL) in women and men (5th quintile: OR = 1.6, 95% CI = 1.0-2.5, P(trend) = 0.02); that was largely due to the effect in men (P(trend) = 0.03). These results do not support a strong role for vitamin D intake with NHL risk, with the exception of a potential association for DLBCL risk in men. Our results should be interpreted conservatively until further investigation in larger pooled studies can be conducted to better assess the role of vitamin D intake in lymphomagenesis.

Multiple indicators of ambient and personal ultraviolet radiation exposure and risk of non-Hodgkin lymphoma (United States)

Recent epidemiologic studies have suggested that ultraviolet radiation (UV) may protect against non-Hodgkin lymphoma (NHL), but few, if any, have assessed multiple indicators of ambient and personal UV exposure. Using the US Radiologic Technologists study, we examined the association between NHL and self-reported time outdoors in summer, as well as average year-round and seasonal ambient exposures based on satellite estimates for different age periods, and sun susceptibility in participants who had responded to two questionnaires (1994-1998, 2003-2005) and who were cancer-free as of the earlier questionnaire. Using unconditional logistic regression, we estimated the odds ratio (OR) and 95% confidence intervals for 64,103 participants with 137 NHL cases. Self-reported time outdoors in summer was unrelated to risk. Lower risk was somewhat related to higher average year-round and winter ambient exposure for the period closest in time, and prior to, diagnosis (ages 20-39). Relative to 1.0 for the lowest quartile of average year-round ambient UV, the estimated OR for successively higher quartiles was 0.68 (0.42-1.10); 0.82 (0.52-1.29); and 0.64 (0.40-1.03), p-trend=0.06), for this age period. The lower NHL risk associated with higher year-round average and winter ambient UV provides modest additional support for a protective relationship between UV and NHL.

Circulating 25-hydroxyvitamin D and risk of non-hodgkin lymphoma: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers

Case-control studies generally suggesting an inverse association between sun exposure and non-Hodgkin lymphoma (NHL) have led to speculation that vitamin D may protect against lymphomagenesis. To examine this hypothesis, the authors conducted a pooled investigation of circulating 25-hydroxyvitamin D (25(OH)D) and subsequent NHL risk within 10 cohorts participating in the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers. The authors analyzed measurements from 1,353 cases and 1,778 controls using conditional logistic regression and other methods to estimate the association of 25(OH)D with NHL. No clear evidence of association between categories of 25(OH)D concentration and NHL was observed overall (P(trend) = 0.68) or by sex (men, P(trend) = 0.50; women, P(trend) = 0.16). Findings for other measures (continuous log(25(OH)D), categories of 25(OH)D using sex-/cohort-/season-specific quartiles as cutpoints, categories of season-adjusted residuals of predicted 25(OH)D using quartiles as cutpoints) were generally null, although some measures of increasing 25(OH)D were suggestive of an increased risk for women. Results from stratified analyses and investigations of histologic subtypes of NHL were also null. These findings do not support the hypothesis that elevated circulating 25(OH)D concentration is associated with a reduced risk of NHL. Future research investigating the biologic basis for the sunlight-NHL association should consider alternative mechanisms, such as immunologic effects.

A case-control study of ultraviolet radiation exposure, vitamin D, and lymphoma risk in adults

Recent research suggests that ultraviolet radiation exposure (UVRE), our major source of vitamin D, is associated with reduced lymphoma risk. Animal and human studies support an association between vitamin D (vitD) insufficiency and increased risk of some malignancies. We conducted a clinic-based case-control study (140 lymphoma cases, 139 controls; 2002-2005, Rochester, NY) to evaluate UVRE and vitD insufficiency in relation to lymphoma risk. Subjects completed a survey and provided a blood sample. We used multivariable logistic regression to estimate lymphoma risk in relation to past (5-10 years prior) UVRE and current vitD insufficiency (determined by serum 25(OH)D). Possible differences in effect by lymphoma subtype were explored, but statistical power was limited. We confirmed the previously reported decrease in lymphoma risk with past UVRE, specifically sunbathing (>once/week versus never); adjusted odds ratio (OR(adj)), = 0.28, 95% confidence interval (CI): 0.10-0.79. Current vitD insufficiency was not associated with lymphoma risk (OR(adj) = 0.89, 95% CI: 0.47-1.72). However, current sunbathing frequency was correlated with measured serum 25(OH)D values. Therefore, while our data do not support an association with current vitD status, development of accurate methods for past vitD assessment to further investigate its role in the association between past UVRE and lymphoma risk is warranted.

Relativism, regulation and the dangers of indifferent science: the Sir Roy Cameron lecture of the Royal College of Pathologists

The evaluation of data obtained from scientific investigations is not easy and the process often seems counterintuitive to the uninformed. Some commentators hold the conviction that ideological motives colour all deliberations-this makes it easy to suggest that in any scientific debate an opponent's reason for holding a particular viewpoint or belief depends on his or her motives, rather than their knowledge base. This position may be useful in providing the grounds on which to mount a polemic against any perceived threat (drugs in modern medicine, pesticides in intensive agriculture or genetically modified organisms). However, its existence is not a reason to ignore the fact that the data obtained by use of the scientific method may be of a different kind from that which depends on opinions, honed by prejudices. Here I use prejudice to mean a bias that may be favourable or unfavourable to a particular viewpoint, rather than to a willful disregard of fact or an unreasoning predilection to arrive at a particular answer--the Precautionary Principle is a good example of only considering results that fit a preconceived viewpoint. The conviction that opinions cannot be based on independent thought has led to a disregard of professionalism and the development of the view that who pays you determines your opinion--not your science. This is relativism, which embodies the assertion that knowledge is relative and that ethical truths depend on the individuals and groups holding them-there are no absolutes. This compounds the problems of regulatory toxicology which is always beset by unavoidable uncertainties and suffers from being based on the use of the results of testing procedures many decades old which have themselves failed to incorporate new knowledge about the processes we investigate (see Hartung, 2009). A more vigorous assertion of the particular values of the scientific viewpoint and a willingness to incorporate new knowledge into regulatory decision making is necessary.

Vitamin D and non-Hodgkin lymphoma risk in adults: a review

Animal and human studies support a protective effect of vitamin D sufficiency related to malignancy by uncovering paracrine and autocrine effects of extra-renal 25-hydroxyvitamin D (25(OH)D) activation including regulation of cell cycle proliferation, apoptosis induction, and increased cell differentiation signaling. Recent epidemiologic studies demonstrate a reduction in non-Hodgkin lymphoma (NHL) risk with increased sunlight exposure. As sunlight is a major vitamin D source, it has been suggested that vitamin D status may mediate this observed association. This review provides a comprehensive discussion of the current epidemiologic evidence with regard to the investigation of an association between vitamin D status and NHL risk.

Dietary vitamin D and risk of non-Hodgkin lymphoma: the multiethnic cohort

The present study explored the association between dietary vitamin D and non-Hodgkin's lymphoma (NHL) risk. The multiethnic cohort (MEC) includes more than 215 000 Caucasians, African Americans, Native Hawaiians, Japanese Americans and Latinos, aged 45-75. After 10 years of follow-up, 939 incident NHL cases were identified. Risk was estimated using proportional hazards' models adjusted for possible confounders. Vitamin D intake was not associated with NHL risk in the entire cohort (P(trend) = 0.72 for men and P(trend) = 0.83 for women), but significantly lowered disease risk in African American women (hazard ratio (HR) = 0.50, 95 % CI: 0.28, 0.90, P(trend) = 0.03) and was borderline protective in African American men (HR = 0.68; 95 % CI: 0.39, 1.19; P(trend) = 0.31) when the highest to the lowest tertile was compared. In NHL subtype analyses, a 19, 36 and 32 % lowered risk, although not significant, was observed for diffuse large B-cell lymphoma, follicular lymphoma and small lymphocytic lymphoma/chronic lymphocytic leukemia in women, respectively. High dietary intake of vitamin D did not show a protective effect against NHL within the MEC except among African Americans, possibly because vitamin D production due to sun exposure is limited in this population.

Assessment of lifetime cumulative sun exposure using a self-administered questionnaire: reliability of two approaches

Few studies have evaluated the reliability of lifetime sun exposure estimated from inquiring about the number of hours people spent outdoors in a given period on a typical weekday or weekend day (the time-based approach). Some investigations have suggested that women have a particularly difficult task in estimating time outdoors in adulthood due to their family and occupational roles. We hypothesized that people might gain additional memory cues and estimate lifetime hours spent outdoors more reliably if asked about time spent outdoors according to specific activities (an activity-based approach). Using self-administered, mailed questionnaires, test-retest responses to time-based and to activity-based approaches were evaluated in 124 volunteer radiologic technologist participants from the United States: 64 females and 60 males 48 to 80 years of age. Intraclass correlation coefficients (ICC) were used to evaluate the test-retest reliability of average number of hours spent outdoors in the summer estimated for each approach. We tested the differences between the two ICCs, corresponding to each approach, using a t test with the variance of the difference estimated by the jackknife method. During childhood and adolescence, the two approaches gave similar ICCs for average numbers of hours spent outdoors in the summer. By contrast, compared with the time-based approach, the activity-based approach showed significantly higher ICCs during adult ages (0.69 versus 0.43, P = 0.003) and over the lifetime (0.69 versus 0.52, P = 0.05); the higher ICCs for the activity-based questionnaire were primarily derived from the results for females. Research is needed to further improve the activity-based questionnaire approach for long-term sun exposure assessment.

A prospective investigation of serum 25-hydroxyvitamin D and risk of lymphoid cancers

Studies indicate that higher sun exposure, especially in the recent past, is associated with reduced risk of non-Hodgkin lymphoma (NHL). Ultraviolet radiation-derived vitamin D may be protective against lymphomagenesis. We examined the relationship between prediagnostic serum 25-hydroxyvitamin D (25(OH)D) and lymphoid cancer risk in a case-control study nested within the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study cohort (1985-2002) of 29,133 Finnish male smokers (ages 50-69). We identified 270 incident lymphoid cancer cases and matched them individually with 538 controls by birth-year and month of fasting blood draw at baseline. In conditional logistic regression models for 10 nmol/L increments or tertile comparisons, serum 25(OH)D was not associated with the risk of overall lymphoid cancers, NHL (n = 208) or multiple myeloma (n = 41). Odds ratios (OR) for NHL for higher tertiles were 0.75 (95% confidence interval (CI), 0.50, 1.14) and 0.82 (95% CI, 0.53, 1.26). The 25(OH)D-NHL association, however, differed by follow-up duration at diagnosis. Cases diagnosed less than 7 years from the baseline showed an inverse association (OR for highest vs. lowest tertile = 0.43; 95% CI: 0.23, 0.83; p for trend = 0.01), but not later diagnoses (OR = 1.52; 95% CI: 0.82, 2.80; p for trend = 0.17). The inverse association found for close exposure to diagnosis was not confounded by other risk factors for lymphoma or correlates of 25(OH)D. Although our findings suggest that circulating 25(OH)D is not likely associated with overall lymphoid cancer, they indicate a potentially protective effect on short-term risk of NHL.