Original Communication
European Journal of Clinical Nutrition (2005) 59, 404–410. doi:10.1038/sj.ejcn.1602088 Published online 22 December 2004
Vitamin D intake and status in Irish postmenopausal women
Guarantor: KD Cashman.
Contributors: TH contributed to design, execution, analysis and writing of the study. AC contributed to dietary assessment and analysis. MOB and AF contributed to design, execution and analysis of the study. MK contributed to design and writing of the study. KDC contributed to design, analysis and writing of the study.
T Hill1, A Collins1, M O'Brien1, M Kiely1, A Flynn1 and K D Cashman1,2
- 1Department of Food and Nutritional Sciences, University College, Cork, Ireland
- 2Department of Medicine, University College, Cork, Ireland
Correspondence: KD Cashman, Department of Food and Nutritional Sciences, University College, Cork, Ireland.E-mail: k.cashman@ucc.ie
Received 28 April 2004; Revised 16 August 2004; Accepted 27 September 2004; Published online 22 December 2004.
Abstract
Objective:
The objective of this study was to assess vitamin D status during late-summer and late-winter/early-spring in postmenopausal Irish women, and whether it was influenced by vitamin D-containing supplement use.
Design:
A longitudinal observational study.
Setting:
Cork City, Ireland (51° north).
Subjects:
A total of 59 apparently healthy, free-living, postmenopausal women aged between 51 and 69 y were sampled during February/March 2002. Of these, 48 and 47 returned during August/September 2002 and February/March 2003, respectively. None of the women were suffering from any medical condition likely to affect vitamin D status. Fasting serums were collected and analysed for 25-hydroxyvitamin D (25 (OH) D) and parathyroid hormone (PTH) by enzyme immunoassays.
Results:
Mean daily intake of vitamin D was 3.2 
g from food sources alone and 5.8 g when vitamin D-containing supplements were included (P<0.01). Serum 25 (OH) D was significantly lower (P<0.001) during February/March 2002 than both August/September 2002 and February/March 2003. Serum 25 (OH) D was also significantly higher (P
0.05) in women who were vitamin D-containing supplement users than nonusers during all three sampling points. Between 17 and 36% of women had inadequate vitamin D status (defined as serum 25 (OH) D <40 nmol/l) during late-winter, but only 4% had inadequate vitamin D status during late-summer. Serum 25 (OH) D was inversely related to serum PTH (r=-0.33; P=0.028).
Conclusion:
Suboptimal vitamin D status is common in postmenopausal Irish women during winter. Vitamin D supplementation is associated with improved vitamin D status, even during summertime.
Sponsorship:
Irish Government under the National Development Plan 2000–2006.
Keywords:
vitamin D, intake, status, postmenopausal women, Irish