Sun Exposure May Reduce Malignant Lymphoma Risk

[Editor-in-Chief]

Sun Exposure May Reduce Malignant Lymphoma Risk



NEW YORK JUN 06, 2007 (Reuters Health) - Recreational sun exposure is apparently associated with reduced risk for malignant lymphoma, German researchers report in the June 1st issue of the International Journal of Cancer.

Reports investigating an association between ultraviolet (UV) light exposure and lymphoma risk have yielded conflicting results, the authors explain, probably because of difficulties in assessing exposure.

Dr. Thomas Weihkopf from Johannes-Gutenberg University, Mainz, and colleagues examined the relationship between malignant lymphoma and UV radiation covering lifetime exposure to different sources of UV exposure, including vacations, outdoor leisure activities, sunbeds, and occupational exposure.

The investigators recruited 710 patients with malignant lymphoma from six regions of Germany and matched them with controls drawn from population registries.

The number of vacations spent in sunny climates was inversely associated with a diagnosis of lymphoma, the researchers report, especially for Hodgkin lymphoma and B-non-Hodgkin lymphoma.

The adjusted odds ratio was 0.6 for more than 1190 cumulative days spent in sunny locations compared with less than 350 days.

Outdoor leisure and occupational activities were not significantly associated with a lymphoma diagnosis, the results indicate, except that high exposure to outdoor leisure activities up to age 15 years was associated with an increased risk of lymphoma, and frequent outdoor leisure activities were significantly associated with T-non-Hodgkin lymphoma and follicular lymphoma.

Frequent sunbed use was associated with a trend toward lower lymphoma diagnosis, the researchers note, and frequent sunbed or sunlamp use was negatively associated with the diagnosis of B-non-Hodgkin lymphoma and diffuse large B-cell lymphoma.

"The results of the 'fully adjusted' regression analysis point to a possible independent protection against malignant lymphoma from vacations at sunny places and from the use of sunbeds," Dr. Weihkopf and associates conclude.

"Possible explanations for this protective effect lie in the stimulation of vitamin D production or in the modulation of T-cell immunology," they suggest.

SOURCE:

• Int J Cancer 2007;120:2445-2451.

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