The Maine studies focused on the way that UVR exposure varies according to latitude, and the effects this seemed to have on the characteristics and health of populations.

缅因医院的研究关注于紫外线照射在不同纬度的变化，其似乎对不同人群的性格和健康都有效果。

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Exposure latitude: its lower limit is at the intersection point of the two curves, with an exposure time of 15 units for the example below.

地理纬度：其下限暴露在交叉点的两曲线，与一个曝光时间15个单位为下面的例子。

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Vitamin D levels, which play a role in the body's immune response and vary with exposure to sunlight, make latitude of residence a possible risk factor.

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