title: Calcium channel blocker use and serum ferritin in adults with hypertension.
abstract: Iron overload cardiomyopathy is becoming more prevalent, and early recognition and intervention may alter outcomes. Calcium channels are key transporters of iron under iron-overloaded conditions, and potentially represent a new therapeutic target for iron overload. The purpose of this study was to examine the relationship between Calcium channel blocker (CCB) use and serum ferritin among adults with diagnosed hypertension. We analyzed the nationally representative NHANES (National Health and Nutrition Examination Survey) 1999-2002 for adults ≥40 years with diagnosed hypertension. The association between CCBs and serum ferritin was assessed using a t-test and adjusted multiple regressions.The study population included 2143 individuals (representing 37.4 million individuals, 42.0 % males). 12.6 % of the population reported taking CCBs in the last month. Individuals taking CCBs had lower mean serum ferritin (129.3 ng/mL versus 154.5 ng/mL, p = 0.02). After adjusting for age, sex, menopause and hysterectomy status for women, race/ethnicity, and C-reactive protein, mean serum ferritin for individuals taking CCBs was 26.3 ng/mL lower than for those not taking CCBs (p = 0.01). In an adjusted regression, individuals who took CCBs and had a daily vitamin C intake of ≥500 mg had a mean serum ferritin that was 60.1 ng/mL lower than people not taking CCBs and with daily vitamin C < 500 mg (p < 0.001). In conclusion, this study found an association between use of CCBs and lower serum ferritin levels in individuals with hypertension. Further studies are needed to assess the possible use of CCBs as non-traditional chelating agents for treatment of iron overload cardiomyopathy.
authors.affiliation: Department of Family Medicine, Medical University of South Carolina, 295 Calhoun St., Charleston, SC 29425, USA. mainouag@musc.edu
authors.forename: Arch G
authors.initials: AG
authors.lastname: Mainous
authors.forename: Eugene D
authors.initials: ED
authors.lastname: Weinberg
authors.forename: Vanessa A
authors.initials: VA
authors.lastname: Diaz
authors.forename: Sharleen P
authors.initials: SP
authors.lastname: Johnson
authors.forename: Mary M
authors.initials: MM
authors.lastname: Hulihan
authors.forename: Althea M
authors.initials: AM
authors.lastname: Grant
mesh_terms: D000328:Adult; D000368:Aged; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D003625:Data Collection; D005260:Female; D005293:Ferritins / Q000097:blood*; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy*; D019190:Iron Overload / Q000097:blood / Q000188:drug therapy; D008297:Male; D008875:Middle Aged
chemical_list: D002121:Calcium Channel Blockers; D005293:Ferritins