Solar activity and urinary melatonin levels in the US-based Nurses’ Health Study, Nurses’ Health Study II, and the Growing Up Today Study
Year: 2022
Type: conference-abstract
Abstract: BACKGROUND AND AIM: The Sun’s magnetic field flips over the course of an 11-year period, oscillating between increased and reduced solar activity, referred to as a solar cycle. These fluctuations in solar activity during the solar cycle are reflected in variation of solar electromagnetic radiation and of geomagnetic disturbances. Solar activity has been linked to adverse health effects, potentially due to circadian disruption. We evaluated the associations between urinary melatonin (6-sulfatoxymelatonin) and solar activity exposures (sunspot number, Kp index, and interplanetary magnetic field strength (IMF)) in the prospective US-based Nurses’ Health Study (NHS), Nurses’ Health Study II (NHSII), and Growing Up Today Study (GUTS) cohorts. METHODS: From 1996 to 2017, 7,936 participants from NHS, NHSII, and GUTS provided urinary samples that were assayed for 6-sulfatoxymelatonin (aMT6). Daily exposures to sunspot number, Kp index, and IMF were estimated from NASA Goddard Space Flight Center. We used Spearman correlations and linear regression to estimate the beta coefficients for a one standard deviation increase in each solar activity exposure on log-transformed aMT6 adjusted for creatinine. We examined same day and 7-day moving average exposures, and adjusted for age, sex, BMI (body mass index), time of urine collection, seasonality, if the urine was a first morning sample, and UV (ultraviolet) exposure. RESULTS: There were statistically significant negative correlations between all of the solar exposures and aMT6. However, after adjustment for potential confounders, there were no associations between same-day exposures to sunspot number (0.28; 95% CI: -0.072, 0.016), Kp index (0.012; 95% CI: -0.019, 0.044), or IMF (-0.005; 95% CI: -0.036, 0.025) and aMT6. Similarly, we found no associations with 7-day moving averages. CONCLUSIONS: In these three prospective US-based cohorts, we did not find evidence of an association between solar activity exposures and urinary melatonin after adjustment for potential confounders. KEYWORDS: Solar activity, melatonin
Source: ISEE Conference Abstracts
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W4317181747