A new Canadian study on vitamin D benefits suggests that women who get just a few hours of sunshine each day have a significantly lower risk of developing breast cancer. Positive Health Wellness The study, performed by Cancer Care Ontario and funded by the Canadian Breast Cancer Research Alliance, involved more than 6,000 women from 25 to 74 years of age. It focused primarily on the effects of vitamin D produced as a result of sun exposure rather than dietary vitamin D, with a goal of determining whether there is a significant association between sun exposure and breast cancer risk.
The participants included about 6,000 women, roughly half of whom had been diagnosed with breast cancer. The remaining women, who did not have the desease, formed a control group. Both groups completed questionnaires on breast cancer risk factors and dietary habits, and were asked to provide information about their amount of sun exposure during various periods of life (teens, 20s-30s, 40s-50s, and 60-75).
The analysis of the participant data indicated that women who spent the most time outdoors (more than 21 hours per week) had significantly lower risk of developing tumors than those who spent the least time outdoors (less than six hours per week). The results of the analysis were striking:
Women who spent the most time outdoors during their teenage years had a 29% lower risk of breast cancer than those who spent the least time outdoors during the same period
Women who spent the most time outside during their 20s and 30s had a 36% lower risk than those who spent the least time outdoors during the same two decades
Women who spent the most time outdoors during their 40s and 50s demonstrated a 26% lower risk of breast cancer than those who spent the least time outside
Women between 60 and 75 who spent the most time outdoors lowered their risk of breask cancer by an astounding 50% as compared to women of the same age who spent the least time outside.
The researchers noted that because most of the participants were Caucasian, further studies will be needed to determine if the results hold true for other ethnic groups.
In addition, the study did not take into account a number of other factors that could potentially effect the women’s risk for breast cancer. Noting that family history, general activity levels, and the onset ages for menstruation and menopause could all have some impact on breast cancer risk, the researchers said their influence would not chance the odds ratio by more than 10%.