Eating higher levels of fish, including tuna and non-fried fish, appears to be associated with a higher risk of malignant melanoma, suggests a large U.S. adult study published. Causes and control of cancer.
Corresponding author Eunyoung Cho said, “Melanoma is the fifth most common cancer in the United States and the lifetime risk of developing melanoma is one in 38 for whites, one in 1,000 for blacks and one in 167. for Hispanics1. Although fish intake has increased in the United States and Europe over the past few decades, the results of previous studies investigating associations between fish consumption and melanoma risk have been inconsistent. Our findings identified an association that requires further investigation. “
Researchers at Brown University in the United States found that, compared to those whose average daily fish intake was 3.2 grams, the risk of malignant melanoma was 22% higher among those whose average daily intake was of 42.8 grams. They also found that those whose median daily intake was 42.8 grams of fish had a 28% increased risk of developing abnormal cells only in the outer layer of the skin – known as stage 0 melanoma or melanoma in situ – compared to those. whose median daily intake was 3.2 grams of fish. One serving of fish is approximately 140 grams of cooked fish.
To examine the relationship between fish consumption and melanoma risk, the authors analyzed data collected from 491,367 adults who were recruited from across the United States for the NIH-AARP Diet and Health Study between 1995 and 1996. Participants , who were 62 years old on average, reported how often they ate fried fish, non-fried fish, and tuna over the previous year, as well as their portion sizes.
Researchers calculated the incidence of new melanomas that developed over a median of 15 years using data obtained from cancer registries. They took into account socio-demographic factors, as well as participants’ BMI, physical activity levels, smoking history, daily alcohol, caffeine and calorie intake, family history of cancer, and average UV radiation levels in their local area. 5,034 participants (1.0%) developed malignant melanoma during the study period and 3,284 (0.7%) developed stage 0 melanoma.
The researchers found that higher intake of non-fried fish and tuna was associated with higher risks of malignant melanoma and stage 0 melanoma. Those whose median daily intake of tuna was 14.2 grams had a 20% higher risk of malignant melanoma and a 17% higher risk of stage 0 melanoma, compared to those whose average daily tuna intake was 0.3 grams. A median intake of 17.8 grams of non-fried fish per day was associated with an 18% higher risk of malignant melanoma and a 25% higher risk of stage 0 melanoma, compared with a median intake of 0.3 grams of non-fried fish per day. Researchers did not identify significant associations between fried fish consumption and the risk of malignant melanoma or stage 0 melanoma.
Eunyoung Cho said: “We hypothesize that our findings can be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic and mercury. Previous research has found that higher fish intake is associated with higher levels of these contaminants at all. body and identified associations between these contaminants and a higher risk of skin cancer. However, we note that our study did not investigate the concentrations of these contaminants in the participants’ bodies and therefore more research is needed to confirm this relationship. “.
The researchers caution that the observational nature of their study does not allow conclusions to be drawn about a causal relationship between fish intake and melanoma risk. In addition, their analyzes did not take into account certain risk factors for melanoma, such as moles, hair color, history of severe sunburn, and sun-related behaviors. Also, since the average daily fish intake was calculated at the start of the study, it may not be representative of the participants’ lifelong diets.
The authors suggest that future research is needed to study the components of fish that could contribute to the observed association between fish intake and melanoma risk and any biological mechanisms underlying this. At the moment, they do not recommend changes to fish consumption.
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