{"id":6153,"date":"2026-10-19T09:48:34","date_gmt":"2026-10-19T09:48:34","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-heilbrigdisvisindum-hrafnhildur-eymundsdottir\/"},"modified":"2026-10-19T09:48:34","modified_gmt":"2026-10-19T09:48:34","slug":"doktorsvorn-i-heilbrigdisvisindum-hrafnhildur-eymundsdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-heilbrigdisvisindum-hrafnhildur-eymundsdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed heilbrig\u00f0isv\u00edsindum – Hrafnhildur Eymundsd\u00f3ttir"},"content":{"rendered":"
\n
\n

F\u00f6studaginn 26. j\u00fan\u00ed ver Hrafnhildur Eymundsd\u00f3ttir doktorsritger\u00f0 s\u00edna \u00ed heilbrig\u00f0isv\u00edsindum vi\u00f0 Matv\u00e6la- og n\u00e6ringarfr\u00e6\u00f0ideild H\u00e1sk\u00f3la \u00cdslands. V\u00f6rninni ver\u00f0ur streymt: https:\/\/livestream.com\/hi\/hrafnhildureysteinsdottir<\/a><\/p>\n

Ritger\u00f0in ber heiti\u00f0: L\u00edfsst\u00edll, D- v\u00edtam\u00edn b\u00faskapur og tengsl vi\u00f0 vitr\u00e6na getu \u00e1 me\u00f0al aldra\u00f0ra; L\u00fd\u00f0grundu\u00f0 h\u00f3pranns\u00f3kn bygg\u00f0 \u00e1 \u00d6ldrunarranns\u00f3kn Hjartaverndar. Lifestyle, 25 hydroxyvitamin D and the associations with cognitive function among older adults; A population-based cohort study using the Icelandic Heart Association\u00b4s AGES-Reykjavik studies.<\/p>\n

Andm\u00e6lendur eru dr. Timo Strandberg, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed Helsinki, og dr. Sigr\u00ed\u00f0ur L\u00e1ra Gu\u00f0mundsd\u00f3ttir, d\u00f3sent vi\u00f0 Menntav\u00edsindasvi\u00f0.<\/p>\n

Lei\u00f0beinendur og umsj\u00f3narkennarar voru Alfons Ramel, pr\u00f3fessor vi\u00f0 Matv\u00e6la- og n\u00e6tringarfr\u00e6\u00f0ideild, og Milan Chang Gu\u00f0j\u00f3nsson, d\u00f3sent vi\u00f0 Menntav\u00edsindasvi\u00f0.<\/p>\n

Gu\u00f0j\u00f3n \u00deorkelsson, pr\u00f3fessor og varadeildarforseti Matv\u00e6la- og n\u00e6ringarfr\u00e6\u00f0ideildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 10:00.\u00a0<\/strong><\/p>\n

\u00c1grip<\/strong><\/p>\n

Helstu orsaka\u00fe\u00e6ttir v\u00e6grar vitr\u00e6nnar sker\u00f0ingar (e. mild cognitive impairment) og heilabilunar eru h\u00e6kkandi aldur, erf\u00f0ir og l\u00e1gt menntunarstig. Ranns\u00f3knir gefa til kynna a\u00f0 hollir lifna\u00f0arh\u00e6ttir geti m\u00f6gulega haft \u00e1hrif \u00e1 heilaheilsu og jafnvel minnka\u00f0 l\u00edkur \u00e1 v\u00e6gri vitr\u00e6nni sker\u00f0ingu og heilabilun \u00e1 efri \u00e1rum.<\/p>\n

Markmi\u00f0 \u00feessarar doktorsranns\u00f3knar var \u00fev\u00ed a\u00f0 rannsaka m\u00f6guleg tengsl l\u00edfsst\u00edls\u00fe\u00e1tta vi\u00f0 vitr\u00e6na getu og heilabilun \u00e1 me\u00f0al aldra\u00f0ra \u00cdslendinga (> 65 \u00e1ra). S\u00e9rst\u00f6k \u00e1hersla var l\u00f6g\u00f0 \u00e1 a\u00f0 rannsaka \u00e1hrif D-v\u00edtam\u00edns (25-hydroxy- D v\u00edtam\u00edn (25OHD)), hreyfingar og l\u00edkams\u00feyngdarstu\u00f0uls \u00e1 vitr\u00e6na getu og heilabilun.<\/p>\n

\u00cd fyrsta \u00e1fanga voru \u00e1hrif D-v\u00edtam\u00edns \u00e1 \u00fer\u00f3un vitr\u00e6nnar getu ranns\u00f6ku\u00f0 og \u00e1hrif hreyfingar sko\u00f0u\u00f0 s\u00e9rstaklega \u00ed \u00feessu samhengi. \u00cd \u00f6\u00f0rum \u00e1fanga var ger\u00f0 ranns\u00f3kn \u00e1 l\u00edfsst\u00edls\u00fe\u00e1ttum einstaklinga sem h\u00f6f\u00f0u greinst me\u00f0 heilabilun og v\u00e6ga vitr\u00e6na sker\u00f0ingu og \u00feeir bornir saman vi\u00f0 einstaklinga sem ekki h\u00f6f\u00f0u greinst me\u00f0 vitr\u00e6nar breytingar. \u00de\u00e1 voru tengsl l\u00edfsst\u00edls\u00fe\u00e1tta vi\u00f0 styrk D-v\u00edtam\u00edns ranns\u00f6ku\u00f0 s\u00e9rstaklega innan \u00feessara h\u00f3pa. \u00cd \u00feri\u00f0ja \u00e1fanga voru breytingar \u00e1 l\u00edkams\u00feyngd aldra\u00f0ra sem voru \u00e1n heilabilunar, rannsaka\u00f0ar me\u00f0 langt\u00edma eftirfylgni og m\u00f6guleg \u00e1hrif \u00e1 vitr\u00e6na getu metin. Jafnframt var rannsaka\u00f0 hvort breytingar \u00e1 l\u00edkams\u00feyngd tengdust v\u00e6gri vitr\u00e6nni sker\u00f0ingu og\/e\u00f0a heilabilun. Ritger\u00f0in er bygg\u00f0 \u00e1 \u00feremur v\u00edsindagreinum sem ver\u00f0a birtar \u00ed al\u00fej\u00f3\u00f0legum v\u00edsindat\u00edmaritum.\u00a0<\/p>\n

Ni\u00f0urst\u00f6\u00f0ur s\u00fdndu a\u00f0 \u00feri\u00f0jungur \u00fe\u00e1tttakenda reyndist me\u00f0 of l\u00e1gan styrk D-v\u00edtam\u00edns. \u00a0Einstaklingar me\u00f0 of l\u00e1gan styrk D-v\u00edtam\u00edns voru markt\u00e6kt l\u00edklegri til a\u00f0 s\u00fdna fram \u00e1 lakari frammist\u00f6\u00f0u \u00e1 vitr\u00e6num pr\u00f3fum heldur en einstaklingar sem voru me\u00f0 e\u00f0lilegan styrk D-v\u00edtam\u00edns. J\u00e1kv\u00e6\u00f0ir l\u00edfsst\u00edls\u00fe\u00e6ttir til a\u00f0 mynda hreyfing og reykleysi, reyndust markt\u00e6kt tengdir h\u00e6rri D-v\u00edtam\u00ednstyrk. \u00cd a\u00f0skildum \u00fatreikningum kom \u00ed lj\u00f3s a\u00f0 hreyfing var tengd betra gengi \u00e1 vitr\u00e6num pr\u00f3fum. Breytingar \u00e1 l\u00edkams\u00feyngd \u00fear sem einstaklingar misstu \u00feyngd \u00e1 ranns\u00f3knart\u00edmabili voru markt\u00e6kt tengdar auknum l\u00edkum \u00e1 vitr\u00e6nni sker\u00f0ingu \u00e1samt aukinni \u00e1h\u00e6ttu \u00e1 v\u00e6gri vitr\u00e6nni sker\u00f0ingu sem \u00ed sumum tilfellum, getur talist undanfari heilabilunar. \u00c1 hinn b\u00f3ginn reyndist aukning \u00e1 l\u00edkams\u00feyngd vera tengd aukinni \u00e1h\u00e6ttu \u00e1 heilabilun en \u00feyngdarbreytingar voru \u00e1vallt bornar saman vi\u00f0 \u00feann h\u00f3p sem var st\u00f6\u00f0ugur \u00ed \u00feyngd.\u00a0<\/p>\n

Til samanbur\u00f0ar vi\u00f0 einstaklinga sem h\u00f6f\u00f0u e\u00f0lilega vitr\u00e6na getu reyndust einstaklingar sem greinst h\u00f6f\u00f0u me\u00f0 heilabilun hafa markt\u00e6kt l\u00e6gri styrk D-v\u00edtam\u00edns. Jafnvel \u00fe\u00f3 a\u00f0 j\u00e1kv\u00e6\u00f0ur l\u00edfst\u00edll hafi tengst auknum styrk D-v\u00edtam\u00edns \u00ed bl\u00f3\u00f0i \u00e1 me\u00f0al einstaklinga sem ekki h\u00f6f\u00f0u heilabilun var sl\u00edka tengingu ekki a\u00f0 finna \u00e1 me\u00f0al einstaklinga me\u00f0 heilabilun.<\/p>\n

Heildarni\u00f0urst\u00f6\u00f0ur benda til \u00feess a\u00f0 D-v\u00edtam\u00edn og hreyfing hafi markt\u00e6k \u00e1hrif \u00e1 vitr\u00e6na getu \u00e1 me\u00f0al einstaklinga \u00e1n heilabilunar. Jafnframt benda ni\u00f0urst\u00f6\u00f0ur til \u00feess a\u00f0 breytingar \u00e1 l\u00edkams\u00feyngd \u00e1 me\u00f0al aldra\u00f0ra s\u00e9u mikilv\u00e6gur \u00fe\u00e1ttur og hafi m\u00f6gulegt forsp\u00e1rgildi \u00feegar kemur a\u00f0 vitr\u00e6nni getu og auki \u00e1h\u00e6ttu \u00e1 heilabilun. \u00a0\u00a0<\/p>\n

H\u00e6kkandi aldri fylgir aukin \u00e1h\u00e6tta \u00e1 vitr\u00e6nni sker\u00f0ingu og heilabilun. L\u00edfsg\u00e6\u00f0i, sj\u00e1lfst\u00e6\u00f0i og f\u00e6rni einstaklings til daglegra athafna er h\u00e1\u00f0 vitr\u00e6nni getu. Ni\u00f0urst\u00f6\u00f0ur \u00feessarar ranns\u00f3knar gefa til kynna a\u00f0 D-v\u00edtam\u00edn, hreyfing og l\u00edkams\u00feyngdarstu\u00f0ull s\u00e9u mikilv\u00e6gir \u00fe\u00e6ttir og tengist markt\u00e6kt vitr\u00e6nni getu og \u00e1h\u00e6ttu \u00e1 heilabilun. Ni\u00f0urst\u00f6\u00f0ur benda til \u00feess a\u00f0 \u00fe\u00f6rf s\u00e9 \u00e1 forv\u00f6rnum gegn heilabilun me\u00f0 fr\u00e6\u00f0slu til heilbrig\u00f0ra l\u00edfsh\u00e1tta.\u00a0<\/p>\n

Abstract<\/strong><\/p>\n

Age and genetics are the main non-modifiable risk factors associated with mild cognitive impairment and dementia. Studies indicate that a positive lifestyle may effect brain health and possibly influence the risk of developing mild cognitive impairment and dementia in older age.\u00a0<\/p>\n

The aim of this thesis was therefore to evaluate lifestyle factors and the associations with cognitive function and the development of dementia among older adults with special considerations for vitamin D, physical activity and body mass index.<\/p>\n

The first phase of this study was to investigate the association between 25-hydroxyvitamin D (25OHD) and cognitive function with particular consideration of physical activity in Icelandic older adults. The second phase investigated lifestyle and 25-hydroxyvitamin D levels (25OHD) in old adults with dementia, mild cognitive impairment or normal cognitive status.<\/p>\n

The third phase investigated longitudinal associations between changes in body weight and declines in cognitive function and risk of mild cognitive impairment\/dementia among community dwelling old adults, with normal cognitive function at baseline.<\/p>\n

According to results of this study, lifestyle is associated with cognitive function among older adults. Around a third of the participants who were free from dementia had either deficient or insufficient levels of vitamin D and those who were deficient were more likely to have lower cognitive function, in all three domains, as compared to normal vitamin D levels. Higher physical activity was related to higher cognitive function. Older people living in the community in Iceland with dementia, have lower 25OHD compared to healthy individuals. Although participants with dementia had poorer lifestyle than healthy participants, differences in lifestyle did not fully explain the observed lower levels of 25OHD in the dementia group. Individuals who lost weight had higher risk of declining cognitive function, while separated analysis showed that weight gain might contribute to the risk of developing dementia. Significant body weight changes in older adulthood may, independently, indicate impending changes in cognitive function. When preventing cognitive decline and dementia among older adults, public health care systems should generally consider lifestyle approach.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Hrafnhildur Eymundsd\u00f3ttir er f\u00e6dd \u00ed Reykjav\u00edk \u00e1ri\u00f0 1981. H\u00fan lauk BA-pr\u00f3fi \u00ed f\u00e9lagsfr\u00e6\u00f0i fr\u00e1 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2009 og MPH-pr\u00f3fi \u00ed l\u00fd\u00f0heilsufr\u00e6\u00f0i fr\u00e1 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2013. \u00c1ri\u00f0 2015 innrita\u00f0ist h\u00fan \u00ed doktorsn\u00e1m vi\u00f0 Matv\u00e6la- og n\u00e6ringarfr\u00e6\u00f0ideild. Samhli\u00f0a doktorsn\u00e1minu hefur Hrafnhildur starfa\u00f0 sem deildarstj\u00f3ri vi\u00f0 Ranns\u00f3knarstofu H\u00e1sk\u00f3la \u00cdslands og Landsp\u00edtalans \u00ed \u00f6ldrunarfr\u00e6\u00f0um og veri\u00f0 a\u00f0sto\u00f0arkennari vi\u00f0 H\u00e1sk\u00f3la \u00cdslands. Foreldrar Hrafnhildar eru Emil\u00eda Sveinbj\u00f6rnsd\u00f3ttir og Eymundur J\u00f3hannsson. Eiginma\u00f0ur hennar er \u00d3lafur P\u00e1ll Snorrason, vi\u00f0skiptafr\u00e6\u00f0ingur. B\u00f6rn \u00feeirra er Ind\u00edana, Mikael og Kolfinna.<\/p>\n<\/div><\/div>","protected":false},"featured_media":2083,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2020-06-26T10:00:00+00:00","_phd_date_end":"2020-06-26T13:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"L\u00edfsst\u00edll, D- v\u00edtam\u00edn b\u00faskapur og tengsl vi\u00f0 vitr\u00e6na getu \u00e1 me\u00f0al aldra\u00f0ra; L\u00fd\u00f0grundu\u00f0 h\u00f3pranns\u00f3kn bygg\u00f0 \u00e1 \u00d6ldrunarranns\u00f3kn Hjartaverndar. Lifestyle, 25 hydroxyvitamin D and the associations with cognitive function among older adults; A population-based cohort study using the Icelandic Heart Association\u00b4s AGES-Reykjavik studies","_phd_source_url":"https:\/\/gamli.hi.is\/vidburdir\/doktorsvorn_i_heilbrigdisvisindum_hrafnhildur_eymundsdottir","_phd_source_node_id":"344025","_phd_source_type":"vidburdir","_phd_member_id":656,"footnotes":""},"phd_school":[60,119],"phd_discipline":[68],"class_list":["post-6153","phd_defence","type-phd_defence","status-publish","has-post-thumbnail","hentry","phd_school-heilbrigdisvisindasvid","phd_school-thverfraedilegt-framhaldsnam","phd_discipline-phd-i-heilbrigdisvisindum"],"_links":{"self":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6153","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence"}],"about":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/types\/phd_defence"}],"version-history":[{"count":0,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6153\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media\/2083"}],"wp:attachment":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media?parent=6153"}],"wp:term":[{"taxonomy":"phd_school","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_school?post=6153"},{"taxonomy":"phd_discipline","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_discipline?post=6153"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}