Abstract
Purpose :
The aim os this study is to compare the vitamin D3 levels in tear and blood between indoor and outdoor college students practitioning regular physical activities.
Methods :
36 college students practicing regular physical activities , from different sports, were separated into two groups: one with indoor athletic activities and the other outdoor athletic activities. The indoor group self-reported less than three hours of sun exposure per week. The outdoor group self-reported more than seven hours of sun exposure er week.
All the athletes were in excellent health condition..
Vitamin D3 levels in blood and tear were evaluated in all participants of this study.
Three ml of venous blood were collected for the plasma evaluation; the tear was collected by placing Schirmer stripes in the lower conjunctival sac fundus of the right eye and collected after 5 minutes. Both tear and blood passed the electrochemiluminecence method for evaluation of vitamin D3 levels. For this study we measured the metabolite 25 (OH) vitamin D3.
Results :
Thirty-six college students, 27 women and 9 men, aged 19 to 27 years, averaging 21.75 years , all healthy, were evaluated; 20 students were part of the indoor activity group and 16 were from the outdoor group.
The plasma vitamin D3 level of the indoor group was 25.01 ng / ml, whereas the plasma vitamin D3 level of the outdoor group was 35.55 ng / ml (p <0,05 ). However, in all 36 participants of this study, the levels of vitamin D3 in the tear were higher than 100 ng / ml ( the maximum detection limit of the system used), well above the plasma levels in the two groups of participants ( p <0.01).
Conclusions :
It was observed that in 36 college students practicing regular physical activities, lacrimal levels were much higher than plasma of vitamin D3, both in indoor and outdoor physical activities ( p< 0,01). We also found that there was a significant difference ( p< 0,05) between plasma levels of vitamin D3 between the indoor and outdoor activity groups, with higher levels observed in the outdoor group. This difference was not observed in the lacrimal levels between the two groups. Given the physiological importance of vitamin D3, new studies should be carried out to explain why these values have been shown to be so superior in tear in comparison to plasma , regardless of amount of sun exposure , in either indoor or outdoor physical activities.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.