Vitamin B 6 Status is Associated with Depression Among Women with Inflammation

Depression is the leading cause of disease burden in U.S. women of reproductive age. Inflammation is associated with depression, yet the mechanism for this association remains unclear. Additionally, vitamin B 6 status has been linked to depression and found to be compromised during inflammation. In secondary data analyses, we evaluated the association between inflammation, vitamin B 6 , and depression in non‐pregnant women (19‐45 yrs) from NHANES 2005‐2006. Depression was evaluated with the Patient Health Questionnaire 9 (PHQ‐9); a score of 10 or above denotes clinically significant depression. Inflammation was defined as a C‐reactive protein level above the median (1.8 mg/L). Vitamin B 6 , as plasma pyridoxine‐5′phosphate, was categorized as deficient (<20 nmol/L), insufficient (20‐30 nmol/L) or normal (>30 nmol/L). Overall, 7.7% of women had depression, but this proportion varied by inflammation status: 4.8% of women with no inflammation, compared to 10.4% of women with inflammation had depression (p=0.008). Vitamin B 6 levels were significantly higher (82.1±5.7 vs 54.1±4.6 nmol/L, p=0.005) and PHQ‐9 scores were lower (2.6±0.2 vs 3.7±0.4; p=0.01) in women without inflammation compared to those with inflammation. The PHQ‐9 score for women with no inflammation did not vary by vitamin B 6 status. However, among those with inflammation, women with vitamin B 6 deficiency had significantly higher PHQ‐9 score (6.1±6.8), followed by those with vitamin B 6 insufficiency (3.9±4.9), and those with normal vitamin B 6 status (3.4±4.5) (p<0.01). Understanding the mechanism linking inflammation and vitamin B 6 to depression could lead to new approaches to prevent and treat depression.