Associations of blood pressure, sunlight, and vitamin D in community-dwelling adults

Abstract

Background Vitamin D deficiency/insufficiency is associated with hypertension. Blood pressure and circulating vitamin D concentrations vary with the seasons and distance from the equator suggesting blood pressure varies inversely with the sunshine available (insolation) for cutaneous vitamin D photosynthesis. Methods To determine if the association between insolation and blood pressure is partly explained by vitamin D we evaluated 1104 participants in the Reasons for Racial and Geographic Differences in Stroke (REGARDS) study whose blood pressure and plasma 25-hydroxyvitamin D (25(OH)D) concentrations were measured. Results We found a significant inverse association between systolic blood pressure (SBP) and 25(OH)D concentration and an inverse association between insolation and blood pressure in unadjusted analyses. After adjusting for other confounding variables, the association of solar insolation and blood pressure was augmented,-0.3.5±SE 0.01 mmHg/1SD higher solar insolation, p=0.01. We found the greatest of effects of insolation on SBP were observed in whites (-5.2±SE O.92 mmHg/1SD higher solar insolation, p=0.005) and in women (-3.8±SE 1.7 mmHg, p=0.024). We found that adjusting for 25(OH)D had no effect on the association of solar insolation with SBP. Conclusions We conclude that although 25(OH)D concentration is inversely associated with SBP, 25(OH)D it did not explain the association of greater sunlight exposure with lower blood pressure. Condensed Abstract To determine if the inverse association between solar insolation and blood pressure is partly explained by vitamin D we evaluated 1104 participants in the Reasons for Racial and Geographic Differences in Stroke (REGARDS) study whose blood pressure and plasma 25-hydroxyvitamin D (25(OH)D) concentrations were measured. We found that 25(OH)D concentration varied inversely with SBP and SBP varied inversely with solar insolation but we found that adjusting for 25(OH)D had no effect on the association of solar insolation with SBP. We conclude that 25(OH)D did not explain the association of greater sunlight exposure with lower blood pressure.

The effect of VDR gene polymorphisms and vitamin D level on blood pressure, risk of preeclampsia, gestational age, and body mass index

“…16 The renin-angiotensin system (RAS) plays a central role in the regulation of blood pressure during pregnancy. However, the severity of preeclampsia was not related to the vitamin D level.…”

Countries’ geographic latitude and their human populations’ cholesterol and blood pressure

“…Blood Group system. (Alfred et al 1974) Conversely, hypertension prevalence or blood pressure 141 have been reported to increase with distance north or south of the Equator or with increased 142 solar radiation exposure within single countries (Cabrera et al 2016;Rostand et al 2016) and in 143 studies of smaller groups of countries (Duranton et al 2018;Rostand 1997) than we have 144 analyzed. However, adjusting for vitamin D levels had no effect on the solar radiation-blood 145 pressure relationship in a recent study, suggesting blood pressure's variation by solar radiation 146 blood pressure findings using data from decades ago are consistent with results from decades 155 ago, but since then, the relationship not only has changed in men, it has reversed in women.…”

“…In a small study (n=338) conducted at three sites in British Columbia, plasma cholesterol decreased with increasing latitude, a finding the authors attributed to differences in Rhesus Blood Group system. 15 Conversely, hypertension prevalence or blood pressure have been reported to increase with distance north or south of the Equator or with increased solar radiation exposure within single countries 16,17 and in studies of smaller groups of countries 3,18 than we have analyzed. However, adjusting for vitamin D levels had no effect on the solar radiationblood pressure relationship in a recent study, suggesting blood pressure's variation by solar radiation levels is not mediated by vitamin D. 17 Public availability of high-quality data facilitated our more comprehensive analysis of latitude's and ultraviolet B radiation's relationship with males' and females' cardiovascular risk factors estimated at the national level, around the globe and over decades.…”

“…15 Conversely, hypertension prevalence or blood pressure have been reported to increase with distance north or south of the Equator or with increased solar radiation exposure within single countries 16,17 and in studies of smaller groups of countries 3,18 than we have analyzed. However, adjusting for vitamin D levels had no effect on the solar radiationblood pressure relationship in a recent study, suggesting blood pressure's variation by solar radiation levels is not mediated by vitamin D. 17 Public availability of high-quality data facilitated our more comprehensive analysis of latitude's and ultraviolet B radiation's relationship with males' and females' cardiovascular risk factors estimated at the national level, around the globe and over decades. Our findings contrast with the prior single-country analysis of latitude and cholesterol, suggesting a possible Simpson's paradox, in which findings at a smaller scale of analysis are at odds with findings at a larger scale of analysis.…”

Vitamin D deficiency in relation to the poor functional outcomes in nondiabetic patients with ischemic stroke

“…Opländer et al [ 35 ] found that UVA irradiation of human skin caused a significant drop in BP even at moderate UVA doses. However, another study concluded that although 25(OH)D concentration was inversely associated with SBP, 25(OH)D it did not explain the association of greater sunlight exposure with lower BP [ 36 ]. Finally, the observation of reduced mortality risk with 1,25(OH)2 D supplements amongst patients with renal failure [ 37 ] and general population [ 38 ] supports a possible CVD protective role of vitamin D.…”