title: Consumption of citrus and cruciferous vegetables with incident type 2 diabetes mellitus based on a meta-analysis of prospective study.
abstract: Observational studies and meta-analyses suggested that increased total fruits and vegetables consumption have a protective role in incidence of type 2 diabetes mellitus (T2DM). However, we still don't know whether the subtypes, such as citrus fruits and cruciferous vegetables (CV), have a preventive role.
  
  
  
  We systematically searched the MEDLINE and EMBASE databases up to December 31, 2014. Summary relative risks (SRRs) and 95% confidence intervals (CIs) were calculated using random-effects models.
  
  
  
  Seven distinct prospective cohort studies (five articles) were identified for this study. A total of 16,544 incident cases of type 2 diabetes were ascertained among 306,723 participants with follow-up periods ranging from 4.6 to 24 years. Based on four prospective cohort studies, we found that overall, consumption of CV had a protective role in the T2DM incidence (highest vs. lowest analysis: SRR=0.84, 95% CI: 0.73 to 0.96), with evidence of significant heterogeneity (P=0.09, I(2)=54.4%). This association was independent of the main risk factors for cardiovascular disease: smoking, alcohol use, BMI, and physical activity etc. Consumption of citrus fruits did not have a protective role in the T2DM development (highest vs. lowest analysis: SRR=1.02, 95% CI: 0.96 to 1.08), with no evidence of significant heterogeneity (P=0.49, I(2)=0).
  
  
  
  Higher consumption of CV, but not citrus fruits, is associated with a significantly decreased risk of type 2 diabetes. Further large prospective studies are needed to elucidate both relationships.
authors.affiliation: Department of Geriatrics, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, 266003 Qingdao, Shandong, China.
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Jia
authors.affiliation: Department of Geriatrics, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, 266003 Qingdao, Shandong, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhong
authors.affiliation: Department of Geriatrics, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, 266003 Qingdao, Shandong, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Geriatrics, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, 266003 Qingdao, Shandong, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Geriatrics, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, 266003 Qingdao, Shandong, China.
authors.forename: Guimei
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Geriatrics, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, 266003 Qingdao, Shandong, China. Electronic address: sunsq0011@126.com.
authors.forename: Shuqin
authors.initials: S
authors.lastname: Sun
mesh_terms: D019607:Brassicaceae; D002957:Citrus; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D000072001:Diet, Healthy; D005638:Fruit; D006801:Humans; D015994:Incidence; D016017:Odds Ratio; D011379:Prognosis; D011446:Prospective Studies; D065840:Protective Factors; D064167:Recommended Dietary Allowances; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014675:Vegetables
keywords: Citrus fruits; Cruciferous vegetables; Type 2 diabetes mellitus