Low vitamin D exposure and risk of nasopharyngeal carcinoma: Observational and genetic evidence from a multicenter case-control study

The protective role of vitamin d in nasopharyngeal carcinoma: insights from Mendelian randomization and meta-analysis

BACKGROUND

In recent years, the anti-tumor effects of vitamin D have garnered increasing attention. However, previous epidemiological studies on the relationship between vitamin D and nasopharyngeal carcinoma (NPC) have yielded inconsistent results. This study aims to further explore whether vitamin D helps reduce the risk of NPC through Mendelian randomization (MR) and meta-analysis.

METHODS

Based on the core assumption of MR study, instrumental variables (IVs) for vitamin D, serving as genetic proxies, were obtained from summary data of large genome-wide association study (GWAS). Inverse-variance weighted (IVW) was utilized as the primary MR analytical method to explore the causal relationship between vitamin D and NPC. Sensitivity analyses included heterogeneity testing and horizontal pleiotropy testing. To further validate the robustness of the result, meta-analysis was employed to obtain pooled effects from databases of different sources.

RESULTS

In the discovery cohort, the IVW result suggest that vitamin D is a potential protective factor against NPC (odds ratio (OR) = 0.35, 95% confidence interval (CI): 0.13-0.89, P = 0.028). The finding was further corroborated by two independent replication cohorts [OR = 0.32, 95% CI: 0.13-0.80, P = 0.018 (ukb-d-30890_irnt); OR = 0.34, 95% CI: 0.13-0.90, P = 0.029(ebi-a-GCST90025967)]. Subsequent meta-analysis indicated that vitamin D markedly reduces the risk of NPC (OR = 0.34, 95% CI: 0.19-0.58, P < 0.001). Multiple sensitivity analyses, including heterogeneity analysis and horizontal pleiotropy tests, did not reveal any significant findings (all P > 0.05).

CONCLUSION

This study provides robust evidence that vitamin D significantly reduces the risk of NPC. Through MR and meta-analysis, we have demonstrated a protective role of vitamin D in NPC development. These findings suggest that maintaining adequate vitamin D levels may be a potential strategy for reducing NPC. Further research is warranted to confirm these results and explore the underlying mechanisms involved.

Serum 25-Hydroxyvitamin D Is Inversely Associated with Nasopharyngeal Carcinoma: A Hospital-Based Matched Case-Control Study in Malaysia

Serum 25(OH)D deficiency consistently demonstrated molecular mechanisms through which chronic inflammation is associated with the risk of nasopharyngeal carcinoma (NPC). This study aimed to determine the association between serum 25(OH)D and NPC. A matched case-control study was conducted at two local hospitals. A total of 300 histologically confirmed NPC cases were matched with controls for age, gender, and ethnicity, and assessed for vitamin D status and other nutritional factors. Mean Vitamin D concentration was significantly lower among cases compared to controls (63.17 ± 19.15 nmol/L and 67.34 ± 23.06 nmol/L) (t = -2.41, p = 0.016). Multiple conditional logistic regression analysis indicated that higher levels of serum 25(OH)D were associated with reduced odds of NPC (AOR = 0.73, 95% CI = 0.57-0.94, p = 0.016) controlling for confounders including BMI, physical activity, smoking status, alcohol consumption, consumption of food high in vitamin D, salted fish consumption, and family history of NPC. There was a significant association between inadequate serum 25(OH)D status with accumulation of four risk factors and increased odds of getting NPC using polynomial regression analysis. Increased NPC odds ratios were observed after sequential accumulation of additional risk factors with the presence of inadequate serum 25(OH)D status (OR = 0.54, 95% CI = 0.27, 4.77, p = 0.322, OR = 1.04, 95% CI = 0.64, 1.72, p = 0.267, OR = 1.15, 95% CI = 0.73, 1.80, p = 0.067, OR = 1.93, 95% CI = 1.13, 3.31, p = 0.022, and OR = 5.55, 95% CI = 1.67, 10.3, p < 0.001 respectively). Future research in Malaysia should involve both prospective cohort studies and randomized controlled trials to confirm and further clarify the role of vitamin D in NPC outcomes.