Exposed Body Surface Area-A Determinate for UV Radiant Energy in Human UV Exposure Studies

Erythemal UV radiation exposure during jogging

Jogging is one of the most popular recreational sport activities over four decades and is done at almost all ages to keep fitness and health. Joggers are exposed to solar UV radiation (UVR) and, due to enhanced heat production by physical activity, body coverage by clothes is reduced. This may imply a health risk due to overexposure. However, little research has been undertaken so far to estimate UVR exposure during jogging. Therefore, UVR exposure was measured at seven body sites during jogging under cloud-free conditions for solar elevations between 20° and 60°. Results show that the top of the shoulder is the most exposed body site by receiving 80% of ambient UVR on average and up to 110% under certain conditions. All other body parts receive up to 55% on average and up to 85% in special cases. This indicates further that monotonous body alignment to the sun holds a higher risk than a frequently alternating alignment. Assuming the longest recommended duration for cardiovascular beneficial jogging of 50 min, photosensitive persons need protection of the shoulders from a UV index of 2 onward on an unvaried path and from a UV index of 3 on an all-directional path. Further, results show that measurements of UVR exposure possess an uncertainty of ±15% including mounting.

Warmer Temperatures Are More Predictive Than Solar Radiation for the Number of Skin Cancer Removal Procedures

BACKGROUND

Solar radiation is the primary risk factor for skin cancer, with personal exposure influenced by environmental and behavioral factors. At higher temperatures, behavioral changes increase solar radiation exposure.

OBJECTIVES

Examine the relationships between solar radiation, ambient temperature, age, and skin cancer.

METHODS

For the contiguous United States, we obtained the state mean global horizontal irradiance (GHI), daily maximum temperature, and number of skin cancer removals in the Medicare population. For skin cancer removals, we defined more sun-exposed skin as the head, neck, hands, and feet, and less sun-exposed skin as the trunk, arms, and legs.

RESULTS

By comparing the temperature thresholds 17°C, 20°C, 24°C, 27°C, 31°C, and 34°C, we found that the annual number of days above 24°C was the strongest temperature-related predictor of skin cancer removals. Multivariable linear regression showed that the number of days above 24°C predicted more skin cancer removals for all body locations and less sun-exposed skin (p = 0.008 and p = 0.003, respectively), while GHI did not (p = 0.1 and p = 0.8, respectively). GHI only predicted more skin cancer removals for more sun-exposed skin (p = 0.02).

CONCLUSION

More days above 24°C was a better predictor of skin cancer removals than GHI for all skin locations and less sun-exposed skin, suggesting that the behavioral changes occurring at warmer temperatures are more predictive of skin cancer removals than solar irradiance. Due to rising global temperatures, skin cancer incidence may further increase. Temperature-related behavioral changes represent a potential target for skin cancer prevention efforts.

Exploratory study on the body distribution of skin color, pigmentation and, degree of tan in Central European Caucasian Women

It is well known that skin color varies by body site and with season. However, little quantitative data on the topography of skin color and pigmentation are available. Therefore, exploratory cutaneous colorimetric measurements in 20 in central European Caucasian women aged 20 to 60 years have been made at 18 body sites. Tri-stimulus L*a*b*-values, hue, and chroma are considered to describe skin color. Based on the "Individual Typology Angle", the "Degree of Tan" was introduced to quantify the difference between constitutive and facultative pigmentation. Measurements were done in late winter and early summer to estimate potential changes by solar ultraviolet radiation. These measurements made evident that skin color obviously differs across the body in late winter. Even nearby body sites can be recognized as differently colored. A remaining degree of tan was found at permanent and intermittent exposed body sites. The remaining tan was not most pronounced at the permanently exposed sites but on the intermediate ones like the shoulder. In early summer, the degree of tan has most developed at the hands, arms, and instep, followed by the face. This study showed that besides basic differences between body sites in winter, accumulation, and degradation of tan also vary between body sites.

Association between sun-protective behaviors and hypertension: a cross-sectional study from National Health and Nutrition Examination Survey 2009 to 2014

BACKGROUND

In previous studies, sun-protective behaviors increased cardiovascular incidence. Our present article is to further analyze the potential relationship between sun-protective behaviors (staying in the shade, wearing long-sleeved clothing, and applying sunscreen) and hypertension.

METHOD

The present cross-sectional study evaluated 8,613 participants (aged 20-60 years) from the National Health and Nutrition Examination Survey (NHANES) obtained between 2009 and 2014. We performed multiple logistic regression analysis to examine the relationship between sun-protective behaviors and hypertension. Subgroup analysis was then performed. Multiple linear regression analysis was utilized to examine the relationship of sun-protective behaviors and each sun-protective behavior with systolic and diastolic blood pressure, stratified by sex and race.

RESULTS

A total of 8,613 participants (weighted n = 127,909,475) were applied in our study, including 1,694 hypertensive subjects. Our study demonstrated that sun-protective behaviors of the 2-3 category were associated with increased risk of hypertension, but not with higher systolic and diastolic blood pressure. In subgroup analysis, men, Mexican American, and 25 < BMI ≤ 30 who reported sun-protective behaviors (2-3) were prone to hypertension. Multiple linear regression models showed that non-Hispanic white men with sun-protective behaviors (2-3) were positively associated with systolic and diastolic blood pressure. The association between other-Hispanic men with frequent wearing long-sleeved clothing and diastolic blood pressure was positively correlated.

CONCLUSION

Sun-protective behaviors of the 2-3 category could increase the incidence of hypertension, but not increase systolic and diastolic blood pressure. We only found that non-Hispanic white men who reported sun-protective behaviors (2-3) were positively associated with systolic and diastolic blood pressure. These findings suggested that excessive sun-protective behaviors should be avoided.