Medical Health Encyclopedia

Other studies have also reported ethnic differences by specific lymphoma subtypes. For example, follicular lymphomas constitute 20% of all NHLs in Western nations but are very uncommon in Asia and in developing countries.

Family History

The brother or sister of a person with the disease has more than a two times higher risk of NHL than the general population. Some cases of NHL in such cases are due to inherited disorders of the immune system. Studies suggest, however, that such family clusters are more likely to be due to environmental conditions that trigger the genetic factors.

Lifestyle Factors

Because of the rapid rise in NHL, investigators are looking for lifestyle factor that may contribute to this increase.

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Body Weight, Shape, and Exercise. A 2002 study looked for any associations between lymphomas and body weight or shape or amounts of exercise. Overall, the researchers did not find any important relationships between non-Hodgkin's lymphomas and these lifestyle factors.

Dietary Factors. A number of studies have observed an association between an increased risk for non-Hodgkin's lymphomas and high consumption of red meat (beef, pork, and lamb). Some have also found a higher risk with animal fats and trans fatty acids (hydrogenated polyunsaturated fats, which are contained in hard margarines and commercial baked goods and fast foods). There appears to be no higher risk with natural polyunsaturated fats (found in most vegetable and fish oils), and in fact, fish may be protective. Medical evidence suggests that milk may also be protective.

One major study observed a reduction in risk with high intake of vegetables. Another found no protection from vegetables, but did with diets rich in fruit. Vitamin supplements have no effect on NHL.

Despite these kinds of reports, the influence of diet on the development of non-Hodgkin's lymphomas remains speculative.