Efficacy and Safety of Vitamin D Supplementation to Prevent COVID-19 in Frontline Healthcare Workers. A Randomized Clinical Trial.

BACKGROUND: Associations between vitamin D (VD) deficiency and the risk of SARS-CoV-2 infection have been documented in cross-sectional population studies. Intervention studies in patients with moderate to severe COVID-19 have failed to consistently document a beneficial effect. OBJECTIVE: To determine the efficacy and safety of VD-supplementation in the prevention of SARS-CoV-2 infection in highly exposed individuals. METHODS: A double-blind, parallel, randomized trial was conducted. Frontline healthcare workers from four hospitals in Mexico City, who tested negative for SARS-CoV-2 infection, were enrolled between July 15 and December 30, 2020. Participants were randomly assigned to receive 4,000 IU VD (VDG) or placebo (PG) daily for 30 d. RT-PCR tests were taken at baseline and repeated if COVID-19 manifestations appeared during follow-up. Serum 25-hydroxyvitamin D3 and antibody tests were measured at baseline and at day 45. Per-protocol and intention-to-treat analysis were conducted. RESULTS: Of 321 recruited subjects, 94 VDG and 98 PG completed follow-up. SARS-CoV-2 infection rate was lower in VDG than in PG (6.4 vs. 24.5%, p <0.001). The risk of acquiring SARS-CoV-2 infection was lower in the VDG than in the PG (RR: 0.23; 95% CI: 0.09-0.55) and was associated with an increment in serum levels of 25-hydroxyvitamin D3 (RR: 0.87; 95% CI: 0.82-0.93), independently of VD deficiency. No significant adverse events were identified. CONCLUSIONS: Our results suggest that VD-supplementation in highly exposed individuals prevents SARS-CoV-2 infection without serious AEs and regardless of VD status.

Association between Plasmatic Ceramides Profile and AST/ALT Ratio: C14:0 Ceramide as Predictor of Hepatic Steatosis in Adolescents Independently of Obesity.

OBJECTIVE: To assess the association between plasma ceramides and hepatic steatosis (HS) in adolescents, independently of obesity. MATERIALS AND METHODS: Ninety-four adolescents from two previous studies conducted and published by our crew were included. Study subjects were stratified in three groups: normal weight (n = 18), obesity (n = 34), and obesity + HS (n = 42). The presence of HS was defined when ALT/AST ratio was <1. Ceramides subspecies (C14:0, C16:0, C18:0, C24:0, and C24:1) were determined by LC/MS. RESULTS: All ceramides correlated directly with ALT levels and inversely with ALT/AST ratio; the strongest correlation was observed among C14:0 ceramide (r = 0.41 and r = -0.54, resp.; P < 0.001). Furthermore, significant correlations were observed between cholesterol and all ceramides except for C24:1 ceramide. Interestingly ceramides C14:0, C18:0, and C24:1 correlated directly with both fasting insulin and HOMA-IR index. For assessing HS, a cut-off point of 10.3 nmol/L for C14:0 ceramide reported a sensitivity of 92.7% and a specificity of 73.5% when normal weight and obesity groups (n = 52) were compared against obesity + HS group (n = 42). Positive and negative predictive values were 77.5% and 90.2%, respectively. CONCLUSIONS: Plasma ceramides are closely associated with hepatic steatosis in adolescents. C14:0 ceramide could be a novel biomarker of HS independently of obesity.

Epidemiología y genética del sobrepeso y la obesidad: Perspectiva de México en el contexto mundial / Epidemiology and genetics of overweight and obesity: Mexico in the world context

Las tasas de obesidad en el mundo se han incrementado drásticamente en las últimas décadas, particularmente en mujeres en edad reproductiva y en niños escolares y adolescentes. Esto resulta trascendente desde el punto de vista de los retos que los sistemas de salud enfrentarán en las próximas generaciones. Recientemente, las encuestas de nutrición en México y Estados Unidos de Norteamérica muestran una desaceleración moderada en esta escalada en la prevalencia de obesidad, lo que podría reflejar el resultado de los programas de prevención, pero también podría deberse a deficiencias metodológicas aún no identificadas; de cualquier manera, esta desaceleración parece insuficiente para alcanzar en el corto plazo las cifras "ideales" en la prevalencia de obesidad. Desde la perspectiva genética, la evidencia de un polimorfismo como el R230C del gene ABCA1 asociado con obesidad, e identificado sólo en poblaciones amerindias, sugiere mayor susceptibilidad en algunos grupos étnicos. Sin embargo, la susceptibilidad para desarrollar obesidad se podría explicar por la interacción entre variantes de diferentes genes. En conclusión, nuestro país presenta tasas de obesidad cercanas a las de países desarrollados; la prevalencia de obesidad es particularmente alarmante en adolescentes y mujeres en edad reproductiva. Existe evidencia que sugiere que la población mexicana podría tener mayor susceptibilidad, pero son necesarios otros estudios para llegar a esta conclusión.

Obesity rates have drastically increased worldwide, particularly in women in reproductive-age as well as in children. This is relevant for the challenges that the health system will face in the near future. Recently, national surveys in Mexico and United States have shown a moderate decrease in the acceleration rates of obesity. Hopefully such behavior reflects results from preventive programs, or perhaps is due to methodological unidentified issues. Importantly, such decrease seems insufficient to reach the "ideal" prevalence of obesity. From the genetic point of view, based in the presence of the R230C polymorphism in the ABCA1 gene identified only in Amerindian populations it seems that some ethnic groups might be more susceptible to develop obesity. However, it is important to take into account that susceptibility may also be explained by interactions among variants in different genes. In conclusion, obesity prevalence in Mexico is close to those in developed countries, and it is particularly alarming in adolescents and women in reproductive-age. Evidence suggests that Mexican population might present a higher susceptibility, but more studies are needed.