Examining chronic inflammatory markers on blood pressure measures in the presence of vitamin D insufficiency among indigenous cree adults: results from the cross-sectional Multi-Community Environment-and-Health Study inEeyou Istchee, Quebec, Canada

Abstract

ObjectiveHigh blood pressure (BP) is a risk factor for cardiovascular disease. Examining the role of inflammatory mediators on BP is important since vitamin D (VD) is a modifiable risk factor, which possibly modulates inflammatory cytokines. This study simulated what are known as average ‘controlled direct effects (CDE)’ of inflammatory markers, C reactive protein (CRP), tumour necrosis factor-α (TNF-α), and interlukin-6 (IL-6) on continuous BP measures, while fixing VD, an intermediate variable to specific level.DesignCross-sectional study.SettingWe analysed data from the Multi-Community Environment-and-Health Study, 2005–2009, conducted in Eeyou Istchee, Quebec, Canada.ParticipantsThis study recruited 1425 study Indigenous Cree participants from seven Cree communities. Only adults with serum VD levels, inflammatory markers and BP measures were included in this data analysis.Primary and secondary outcomes measuresInflammatory markers examined the top 25th exposure percentiles. VD ‘insufficiency’ (ie, 25-hydroxyvitamin-D levels<50 nmol/L) defined by the Institute of Medicine. CDE for each inflammatory marker in the presence and absence of population VD insufficiency simulated the average direct effect change for systolic and diastolic BP (SBP and DBP) measures. All models were adjusted for exposure-and-mediator outcome relationship.ResultsAmong 161 participants, 97 (60 %) were female. The prevalence of VD insufficiency was 32%. CDE estimates show in the presence and absence of population vitamin D insufficiency, inflammatory markers have a slightly different association on BP. TNF-α significantly and inversely associated with SBP in the presence of vitamin D insufficiency, fully adjusted model β = −13.61 (95% CI −24.42 to −2.80); however, TNF-α was not associated with SBP in the absence of vitamin D insufficiency. CRP, IL-6 were also not significantly associated with BP measures, although the magnitude of association was greater for those with elevated inflammation and VD insufficiency.ConclusionThis novel analysis shows in the presence of VD insufficiency, inflammation (particularly TNF-α) may affect SBP. Additional research is needed to elucidate these findings, and the temporal relationship between these variables.

Independent Association of 25[OH]D Level on Reduced Glutathione and TNF-α in Patients ‎with Diabetes and/or Hypertension

“…49 Supplementation of T2DM patients with 25[OH]D was shown to cause an improvement of their inflammatory status. 50 Similarly, in hypertensive patients, a correlation was established between 25[OH]D insufficiency and SBP in hypertensive patients, 51 which was contrary to the results of the current study where there was no correlation of the level of 25[OH]D with TNF-α in either T2DM or hypertensive patients. An explanation for such discrepancy may be due to the increment of GSH seen in the present study that might blunt the oxidative stress, which might be a main determinant factor of induction of inflammatory pathway.…”

Association of serum Vitamin D 、C-reactive protein with multiple causes of death outcomes in obese adult population: The United States National Health and Nutrition Examination Survey, 2001 to 2006

“…Studies have shown that vitamin D de ciency is a global public health problem and that epidemics often have a more severe impact on the elderly and those with complications such as obesity, diabetes, hypertension, respiratory disease, recurrent infections, immune de ciency, and malignant tumors [12]. Low vitamin D levels are associated with an increased risk of obesity and exacerbated in ammation for health bene ts [13,14]. Adequate vitamin D may prevent obesity and obesity-related diseases by inducing Ca 2+− mediated adipocyte apoptosis through the anti-obesity mechanism of 1,25 (OH) D2D3 [15].…”