TY - JOUR
T1 - No seasonality in the risk of multiple sclerosis in an equatorial country
T2 - A case-control ecological study
AU - Cárdenas-Robledo, Simón
AU - González-Caicedo, Paula
AU - Carvajal-Parra, Michael Steven
AU - Guío-Sánchez, Claudia Marcela
AU - López-Reyes, Lorena
N1 - Publisher Copyright:
© The Author(s), 2022.
PY - 2022
Y1 - 2022
N2 - BACKGROUND: Multiple sclerosis risk has been shown to have seasonal variations that are more pronounced in higher latitudes. However, this phenomenon has not been adequately studied near the Equator.OBJECTIVE: To explore the risk of multiple sclerosis associated with month, season of birth, and sunlight exposure variables in Colombia.METHODS: In this case-control study, 668 multiple sclerosis cases were matched to 2672 controls by sex and age. Association of multiple sclerosis with each month/season of birth and sunlight exposure variables was estimated with multilevel mixed-effects logistic regression and ecological regression models, respectively. Seasonality in the births of multiple sclerosis was assessed with a non-parametric seasonality test.RESULTS: We found a higher probability of multiple sclerosis in September (0.25; 95% confidence interval (CI) = 0.21-0.31) and lower in March (0.15; 95% CI = 0.10-0.18), which turned non-significant after a multiple comparisons test. Sunlight exposure variables had no significant effect on the risk of MS, and the tests of seasonality in the births of MS did not show significant results.CONCLUSION: Our results show no seasonality in the risk of multiple sclerosis near the Equator, supporting the hypothesis that this phenomenon is latitude dependent.
AB - BACKGROUND: Multiple sclerosis risk has been shown to have seasonal variations that are more pronounced in higher latitudes. However, this phenomenon has not been adequately studied near the Equator.OBJECTIVE: To explore the risk of multiple sclerosis associated with month, season of birth, and sunlight exposure variables in Colombia.METHODS: In this case-control study, 668 multiple sclerosis cases were matched to 2672 controls by sex and age. Association of multiple sclerosis with each month/season of birth and sunlight exposure variables was estimated with multilevel mixed-effects logistic regression and ecological regression models, respectively. Seasonality in the births of multiple sclerosis was assessed with a non-parametric seasonality test.RESULTS: We found a higher probability of multiple sclerosis in September (0.25; 95% confidence interval (CI) = 0.21-0.31) and lower in March (0.15; 95% CI = 0.10-0.18), which turned non-significant after a multiple comparisons test. Sunlight exposure variables had no significant effect on the risk of MS, and the tests of seasonality in the births of MS did not show significant results.CONCLUSION: Our results show no seasonality in the risk of multiple sclerosis near the Equator, supporting the hypothesis that this phenomenon is latitude dependent.
KW - Multiple sclerosis
KW - month of birth
KW - risk factors
KW - seasons
KW - sunlight
KW - ultraviolet rays
UR - http://www.scopus.com/inward/record.url?scp=85139955799&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/96e8ce8b-cf58-3478-8b9f-09c22733a177/
U2 - 10.1177/13524585221130020
DO - 10.1177/13524585221130020
M3 - Artículo
C2 - 36250508
SN - 1352-4585
SP - 13524585221130020
JO - Multiple sclerosis (Houndmills, Basingstoke, England)
JF - Multiple sclerosis (Houndmills, Basingstoke, England)
ER -