title: Iodine Status of New Zealand Elderly Residents in Long-Term Residential Care.
abstract: In response to the re-emergence of iodine deficiency in New Zealand, in 2009 the government mandated that all commercially made breads be fortified with iodized salt. There has been no evaluation of the impact of the program on iodine status of the elderly, despite this population group being vulnerable to iodine deficiency or excess. The aim of this study was to describe the iodine status of elderly New Zealanders in residential aged-care homes following the implementation of the bread fortification program. A cross-sectional survey was conducted, involving 309 residents (median age 85 years) from 16 aged-care homes throughout NZ. Information on socio-demographic, anthropometric, dietary and health characteristics were collected. Casual spot urine samples were analysed for urinary iodine concentration (UIC). Blood samples were analysed for serum thyroglobulin, thyroglobulin antibodies, and other biochemical indices. The median UIC (MUIC) of the residents was 72 μg/L, indicating mild iodine deficiency, and 29% had a UIC < 50 μg/L. Median thyroglobulin concentration was 18 ng/mL and 26% had elevated thyroglobulin concentration (>40 ng/mL), suggesting iodine insufficiency. Diuretic use was associated with lower MUIC (p = 0.043). Synthetic thyroxine use was associated with lower odds of having a UIC < 50 μg/L (OR 0.32, p = 0.030)) and lower median thyroglobulin (-15.2 ng/mL, p = 0.001), compared with untreated participants. Frailty was associated with elevated thyroglobulin (p = 0.029), whereas anemia was associated with lower thyroglobulin (p = 0.016). Iodine insufficiency persists in New Zealanders residing in residential aged-care homes despite increasing iodine intake from fortified bread. Research is required to establish optimal iodine intake and status in the elderly.
authors.affiliation: Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. jody.miller@otago.ac.nz.
authors.forename: Jody C
authors.initials: JC
authors.lastname: Miller
authors.affiliation: Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. sue.macdonell@otago.ac.nz.
authors.forename: Sue O
authors.initials: SO
authors.lastname: MacDonell
authors.affiliation: Department of Preventive and Social Medicine, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. andrew.gray@otago.ac.nz.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Gray
authors.affiliation: Trace Element Centre, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. malcolm.reid@otago.ac.nz.
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Reid
authors.affiliation: Trace Element Centre, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. david.barr@otago.ac.nz.
authors.forename: David J
authors.initials: DJ
authors.lastname: Barr
authors.affiliation: Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. christine.thomson@otago.ac.nz.
authors.forename: Christine D
authors.initials: CD
authors.lastname: Thomson
authors.affiliation: Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. lisa.houghton@otago.ac.nz.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Houghton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001939:Bread; D003430:Cross-Sectional Studies; D003677:Deficiency Diseases / Q000453:epidemiology* / Q000208:ethnology / Q000378:metabolism / Q000517:prevention & control; D004032:Diet / Q000009:adverse effects* / Q000208:ethnology; D058620:Elder Nutritional Physiological Phenomena / Q000208:ethnology; D005260:Female; D005527:Food, Fortified; D006707:Homes for the Aged; D006801:Humans; D007455:Iodine / Q000172:deficiency* / Q000627:therapeutic use / Q000652:urine; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D009735:Nursing Homes; D018673:Nutrition Policy; D009749:Nutrition Surveys; D009752:Nutritional Status / Q000208:ethnology; D010349:Patient Compliance / Q000208:ethnology; D015995:Prevalence; D012306:Risk
chemical_list: D015415:Biomarkers; D007455:Iodine
keywords: elderly; iodine; thyroglobulin; urinary iodine