Diabetes Care
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Diabetes Care 31:e26 2008
DOI: 10.2337/dc07-2122
© 2008 by the American Diabetes Association
This Article
Right arrow Extract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Luan, D. C.
Right arrow Articles by Liu, Z. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Luan, D. C.
Right arrow Articles by Liu, Z. M.
Social Bookmarking
Add to CiteULike   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Online Letters: Comments and Responses

Body Iron Stores and Dietary Iron Intake in Relation to Diabetes in Adults in North China

Response to Shi and Pan

De Chun Luan, MD, MPH, Hui Li, MD, Sui Jing Li, MD, Zhuo Zhao, MD, Xin Li, MD and Zhong Mei Liu, MD

From the Institute for Nutrition and Food Safety, Liaoning Provincial Center for Disease Control and Prevention, Shenyang, China

Address correspondence to Sui Jing Li, MD, Institute for Nutrition and Food Safety, Liaoning Provincial Center for Disease Control and Prevention, 42-1 Ji Xian St., Shenyang 110005, China. E-mail: lisuijing88{at}sohu.com

In response to the letter of Shi and Pan (1), we appreciate their interest and willingness to comment on our study (2). First, it does not matter whether the lowest quartile (featuring very low levels of heme iron intake) or higher quartiles are chosen as the reference group because odds ratio is a relative value. In addition, the large range of heme iron intake in the Chinese population is just one strength of a study of the relationship between heme iron intakes and risk of diabetes. Finally, socioeconomic status may influence diabetes development independently as well as through diet. After adjustment for socioeconomic status, the odds ratios across heme iron intake quartiles were 1.00, 1.40 (95% CI 0.75:2.59), 2.12 (1.17–3.84), and 2.54 (1.36–4.75) (P for trend 0.0326), which were not significantly different from the unadjusted values.

Similar positive associations between serum ferritin level and fasting plasma glucose were found in both Shi et al.’s study (3) and ours (2). We found that mean serum ferritin levels increased across heme iron intake quartiles but decreased across nonheme iron intake quartiles. The mean serum ferritin levels across heme iron intake quartiles in our data were 97.17, 99.70, 109.20, and 115.58 µg/l, and the mean serum ferritin levels across nonheme iron intake were 113.43, 110.99, 98.72, and 98.40 µg/l. Thus, nonheme iron intake should not be positively associated with diabetes risk. We found no significant association between nonheme iron intake and diabetes in our data, whereas Lee et al. (4) demonstrated that nonheme iron intake was negatively associated with diabetes.

Dietary iron supply is determined by total iron intake, content of heme iron, and the bioavailability of nonheme iron (5). The absorption of heme iron is constant and independent of meal composition, and its contribution can be readily calculated from dietary records (5). Rajpathak et al.’s study (6) and some other epidemiological studies have also demonstrated the association between heme iron intake and diabetes. It does not seem appropriate to examine the association between nonheme iron intake and diabetes without considering the bioavailability of the former.

References

  1. Shi Z, Pan X: Body iron stores and dietary iron intake in relation to diabetes in adults in North China (Letter). Diabetes Care 31:e25, 2008. DOI:10.2337/dc-2048[Free Full Text]
  2. Luan DC, Li H, Li SJ, Zhao Z, Li X, Liu ZM: Body iron stores and dietary iron intake in relation to diabetes in adults in North China. Diabetes Care 31:285–286, 2008[Abstract/Free Full Text]
  3. Shi Z, Hu X, Yuan B, Pan X, Meyer HE, Holmboe-Ottesen G: Association between serum ferritin, hemoglobin, iron intake, and diabetes in adults in Jiangsu, China. Diabetes Care 29:1878–1883, 2006[Abstract/Free Full Text]
  4. Lee DH, Folsom AR, Jacobs DR Jr: Dietary iron intake and type 2 diabetes incidence in postmenopausal women: the Iowa Women’s Health Study. Diabetologia 47:185–194, 2004[Medline]
  5. Cook JD: Adaptation in iron metabolism. Am J Clin Nutr 51:301–308, 1990[Abstract/Free Full Text]
  6. Rajpathak S, Ma J, Manson J, Willett WC, Hu FB : Iron intake and the risk of type 2 diabetes in women: a prospective cohort study. Diabetes Care 29(6):1370–1376, 2006

Add to CiteULike CiteULike   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?



This Article
Right arrow Extract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Luan, D. C.
Right arrow Articles by Liu, Z. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Luan, D. C.
Right arrow Articles by Liu, Z. M.
Social Bookmarking
Add to CiteULike   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Diabetes Diabetes Care Clinical Diabetes Diabetes Spectrum