Dental Health Articles

Vitamin, Mineral Supplements Linked With Increased Mortality Risk

Posted on October 29th, 2011

Interesting...see highlighted area at the end for the conclusions:)

Arch Intern Med. 2011;171:1625-1633,1633-1634<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

This article is intended for primary care clinicians, geriatricians, gynecologists, and other specialists who care for older women who may be using dietary supplements

Study Highlights

  • The study enrolled 41,386 women 55 to 69 years old at baseline in 1986; these women had completed a 16-page questionnaire.
  • 99.2% were white, and 98.6% were postmenopausal.
  • Those who did not provide information on dietary intake or supplement use at baseline were excluded from the study.
  • For this analysis, 38,772 women were included at baseline in 1986.
  • In the 2004 analysis, 19,124 women were included.
  • A validated 127-item food frequency questionnaire was used to assess food intake, and food composition was derived from the Harvard University Food Composition Database.
  • Supplement use was queried in 1986, 1997, and 2004 and included 15 supplements assessed at all 3 surveys.
  • The supplements included multivitamins, vitamin B6, carotene, vitamin B complex, selenium, and zinc.
  • Different forms of vitamin D were not distinguished.
  • Deaths through 2008 were identified through the State Health Registry of Iowa or the National Death Index.
  • International Classification of Diseases, Ninth Revision, codes were used to identify causes of death.
  • Other information taken included blood pressure, weight, height, use of hormones, physical activity, and smoking status.
  • Among the 38,772 women at baseline, mean age was 61.6 years, and 15,594 (40.2%) died during a follow-up period of 19.0 years.
  • Thus, each sample for each survey had 15% fewer respondents because of death.
  • At baseline, supplement users vs nonusers had lower prevalence of diabetes mellitus, high blood pressure, and smoking. They also had lower body mass index (BMI) and waist-to-hip ratio.
  • In addition, they had higher education, were more likely to be active, and more likely to use estrogen replacement therapy.
  • They had lower intake of calories and fat and higher intake of carbohydrates and proteins.
  • Self-reported use of supplements increased significantly from 1986 to 2004.
  • The prevalence for 1986, 1997, and 2004 was 62.7%, 75.1%, and 85.1%, respectively, for use of at least 1 supplement daily.
  • The most commonly used supplements were calcium, multivitamins, and vitamins C and E.
  • The most common supplement combinations were calcium and multivitamins; calcium, multivitamins, and vitamin C; and calcium and vitamin C.
  • Copper use was associated with an increased risk for mortality.
  • Use of vitamins C, D, E, and calcium was associated with lower mortality risk, but in the adjusted model, only calcium use remained protective (HR, 0.92).
  • Adjustment for nonnutritional factors showed an increased risk for mortality for multivitamins (HR, 1.06), vitamin B6 (HR, 1.09), and iron (HR, 1.09).
  • Further adjustment for nutritional factors strengthened the associations even more: multivitamins (HR, 1.06), vitamin B6 (HR, 1.10), folic acid (HR, 1.15), calcium (HR, 0.91), copper (HR, 1.45), iron (HR, 1.10), magnesium (HR, 1.08), and zinc (HR, 1.08).
  • For iron, the increased risk was 1.35 overall for women who reported use at all 3 surveys.
  • The associations were not affected by exclusion of women with diabetes mellitus or cardiovascular disease.
  • Only calcium remained as protective after multivariate adjustment, with an HR of 0.91.
  • A dose-response association was found for calcium, with loss of protection occurring at the highest doses.
  • No dose-response association was found for other supplements.
  • The authors concluded that commonly used supplements including multivitamins; vitamin B6; folic acid; and the minerals iron, magnesium, zinc, and copper were associated with increased mortality risk but that supplemental calcium was associated with reduced mortality risk.

Clinical Implications

  • Older women who use dietary supplements are more likely to be educated, active, nonsmokers, have a lower BMI, and are less likely to have diabetes or high blood pressure.
  • Use of the most common dietary supplements (ie, multivitamins, vitamin B6, folic acid, iron, magnesium, and zinc) except for calcium is associated with an increased risk for mortality in older women

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