Background: Low serum vitamin D is now implicated in many disease conditions among the elderly including cognitive impairment. Cognitive impairment is a common disease among elderly people causing much financial and social burden to the elderly, their families and caregivers. Therefore, the study aimed to determine the relationship between serum 25-hydroxyvitamin D (25(OH)D) concentration and cognitive function among elderly people in Enugu State, South-eastern Nigeria. Methods: This was a cross-sectional survey of subjects aged ≥ 60 years with cognitive impairment in communities and old People's home in Enugu State in Nigeria and age-and sex-matched controls. The subjects were further divided into those with severe cognitive impairment and those with mild cognitive impairment using the Mini-Mental State Examination (MMSE). Serum 25(OH)D and parathyroid hormone (PTH) were assayed by enzyme-linked immune-sorbent assay while serum calcium, inorganic phosphate, and albumin were determined using the spectrophotometric method. Student t-test was used to compare mean values obtained, while Pearson correlation was used to determine relationships between continuous data. A p-value<0.05 was considered to be statistically significant. Result: One hundred and four (104) patients comprising of 58 males and 46 females were recruited for the current study. Among the study subjects compared to those of the controls, there were significantly decreased levels of serum 25(OH)D (p=0.0001) and the adjusted calcium (p=0.0001) concentrations but significantly increased level of serum PTH (p=0.0001) and inorganic phosphate (p=0.005) concentrations. Also, the mean values of serum 25(OH)D and adjusted calcium were significantly lower, serum PTH values were significantly higher while serum inorganic phosphate concentrations showed no significant difference for those with severe cognitive impairment when compared to values of those with mild cognitive impairment and controls. Additionally, there was also significant positive correlations between serum 25(OH)D and cognitive function (r=0.504, ρ<0.05). Conclusion:The study findings suggest that decreased serum Vitamin D concentration is associated with diminished cognitive function among the elderly and vice versa. Hence, the determination of Vitamin D status among elderly patients presenting with impairment of cognitive function is highly recommended. However, further studies are needed to validate findings from the present study.

Background: Vitamin D deficiency is widely speculated to be associated with prostate cancer (PCa) incidence, progression, aggressiveness, and metastatic potentials. However, evidence of this is limited among the black population. Hence, this study was spurred by the dearth of data in this regard. Methods: This was a prospectively designed/executed casecontrolled descriptive study carried out in the University of Port Harcourt Teaching Hospital (UPTH) in the Niger Delta subregion of Nigeria. Serum Vitamin D level status was determined/compared between the 380 histologically-verified positive PCa cases and the smoking/sex-matched 380 histologically-verified negative controls using descriptive and comparative statistical tools. The relationship/association between PCa grade/stage and Vitamin D level status was ascertained using crude and adjusted regression models. Data were managed and analyzed with the Statistical Package for Social Sciences version 23 and a p-value of <0.05 was deemed statistically significant. Results: The histologically-verified positive PCa patients had significantly lower mean Vitamin D level status (PCa patients: 24.55 ± 3.47 vs. controls: 49.73 ± 4.08; p<0.001) but higher mean prostate volumes, BMI status, plasma intact PTH levels, and total PSA levels compared to the histologically-verified negative controls. A decreasing trend of serum Vitamin level status was observed with worsening/increasing PCa grade and stage (p<0.05) among the biopsy positive PCa cases. An inverse relationship existed between Vitamin D level status and PCa grade/stage among the Vitamin D deficient PCa subgroup (p<0.05) but not the sufficient/insufficient PCa subgroups (p>0.05). Among the Vitamin D deficient PCa patients, this inverse relationship continued to strengthen with worsening PCa grade/stage. When compared with the PCa patients with the lowest PCa grade (ISUP grade 1) and stage (T1), an increased likelihood of Vitamin D deficiency was significantly associated with worsening PCa grade (ISUP 2 to 5) and stage (T2 to T4) on crude multiple logistic regression model which was subsequently amplified following adjusting for observed confounders. Conclusion:The study findings corroborate the epidemiologic evidence of the association of Vitamin D deficiency with PCa grade and stage; factors that define PCa aggressiveness and metastatic potentials. However, more robust studies among populations of the black race are highly recommended to validate conclusions from this current study.