Zumin Shi1, Ming Li2, Youfa Wang3, Jianghong Liu4, Tahra El-Obeid1. 1. Human Nutrition Department, Qatar University, Doha, Qatar. 2. Center for Population Health Research, Division of Health Sciences, University of South Australia, Adelaide, Australia. 3. Global Health Institute, Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China. 4. University of Pennsylvania School of Nursing, Philadelphia, PA.
Abstract
Background: High body iron status has been shown to be associated with adverse health outcomes. However, the relation between high body iron status, body mass index (BMI), and cognition is still understudied. Objective: This study aimed to examine the association between iron intake and cognitive function in Chinese adults and tested the interaction effect of iron intake and BMI on cognition. Design: Longitudinal study data from a nationwide sample (n = 4852; age ≥55 y) from the China Health and Nutrition Survey during 1991-2006 were used. Of the participants, 3302 had completed cognitive screening tests in ≥2 surveys. Cognitive function was assessed in 1997, 2000, 2004, and 2006. Dietary iron intake was obtained from a 3-d food record during home visits in 1991, 1993, 1997, 2000, 2004, and 2006. Multivariable mixed linear regression and logistic regression were used. Results: The cumulative mean ± SD iron intake in 1997 of tested subjects was 23.7 ± 11.3 mg/d (25.4 mg/d in men and 22.2 mg/d in women). High iron intake was associated with poor cognition. In fully adjusted models, across the quartiles of iron intake the regression coefficients (95% CIs) were 0, -0.39 (-0.77, -0.01), -0.55 (-0.95, -0.15), and -0.90 (-1.33, -0.47), respectively. Comparing extreme quartiles of iron intake (high), the OR (95% CI) for poor cognitive function was 1.30 (1.04, 1.64). There was a significant interaction between iron intake and BMI. The association between high iron intake and poor cognition was stronger among those with a high BMI than those with a low BMI. Among those with a BMI (kg/m2) >24, across quartiles of iron intake the ORs (95% CIs) for poor cognitive function were 1.00, 1.27 (0.91, 1.78), 1.41 (0.97, 2.04), and 2.04 (1.38, 3.01), respectively. Conclusion: Higher iron intake is associated with poor cognition in Chinese adults, especially among those with a high BMI.
Background: High body iron status has been shown to be associated with adverse health outcomes. However, the relation between high body iron status, body mass index (BMI), and cognition is still understudied. Objective: This study aimed to examine the association between iron intake and cognitive function in Chinese adults and tested the interaction effect of iron intake and BMI on cognition. Design: Longitudinal study data from a nationwide sample (n = 4852; age ≥55 y) from the China Health and Nutrition Survey during 1991-2006 were used. Of the participants, 3302 had completed cognitive screening tests in ≥2 surveys. Cognitive function was assessed in 1997, 2000, 2004, and 2006. Dietary iron intake was obtained from a 3-d food record during home visits in 1991, 1993, 1997, 2000, 2004, and 2006. Multivariable mixed linear regression and logistic regression were used. Results: The cumulative mean ± SD iron intake in 1997 of tested subjects was 23.7 ± 11.3 mg/d (25.4 mg/d in men and 22.2 mg/d in women). High iron intake was associated with poor cognition. In fully adjusted models, across the quartiles of iron intake the regression coefficients (95% CIs) were 0, -0.39 (-0.77, -0.01), -0.55 (-0.95, -0.15), and -0.90 (-1.33, -0.47), respectively. Comparing extreme quartiles of iron intake (high), the OR (95% CI) for poor cognitive function was 1.30 (1.04, 1.64). There was a significant interaction between iron intake and BMI. The association between high iron intake and poor cognition was stronger among those with a high BMI than those with a low BMI. Among those with a BMI (kg/m2) >24, across quartiles of iron intake the ORs (95% CIs) for poor cognitive function were 1.00, 1.27 (0.91, 1.78), 1.41 (0.97, 2.04), and 2.04 (1.38, 3.01), respectively. Conclusion: Higher iron intake is associated with poor cognition in Chinese adults, especially among those with a high BMI.
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Authors: Nawab Qizilbash; John Gregson; Michelle E Johnson; Neil Pearce; Ian Douglas; Kevin Wing; Stephen J W Evans; Stuart J Pocock Journal: Lancet Diabetes Endocrinol Date: 2015-04-09 Impact factor: 32.069
Authors: Anya Topiwala; Chaoyue Wang; Klaus P Ebmeier; Stephen Burgess; Steven Bell; Daniel F Levey; Hang Zhou; Celeste McCracken; Adriana Roca-Fernández; Steffen E Petersen; Betty Raman; Masud Husain; Joel Gelernter; Karla L Miller; Stephen M Smith; Thomas E Nichols Journal: PLoS Med Date: 2022-07-14 Impact factor: 11.613