title: Long-term adherence and effects on grip strength and upper leg performance of prescribed supplemental vitamin D in pregnant and recently pregnant women of Somali and Swedish birth with 25-hydroxyvitamin D deficiency: a before-and-after treatment study.
abstract: Muscular weakness and severe vitamin D deficiency is prevalent in Somali (veiled) pregnant women, Sweden. The study aims here were to explore adherence to prescribed supplemental vitamin D in new mothers with vitamin D deficiency and its effects on grip strength and upper leg performance in Somali (target group TG) and Swedish women (reference group RG) from spring through winter.
  
  
  
  A before- and after study was designed. A cross-sectional sample of women in antenatal care with serum 25-OHD ≤50 nmol/L were prescribed one or two tablets daily (800 or 1600 IU vitamin D3 with calcium) for 10 months. Reminders were made by Somali nurses (TG) or Swedish doctors (RG). Baseline and 10 month measurements of plasma nmol/L 25-OHD, maximal grip strength held for 10 s (Newton, N) and ability to squat (yes;no) were done. Total tablet intake (n) was calculated. Outcome variables were changes from baseline in grip strength and ability to squat. Predicting variables for change in grip strength and ability to squat were calculated using linear and binary regression in final models. Undetectable 25-OHD values (<10 nmol/L) were replaced with '9' in statistic calculations.
  
  
  
  Seventy-one women (46 TG, 1/3 with undetectable baseline 25-OHD; 25 RG) participated. At the 10-month follow up, 17% TG and 8% RG women reported having refrained from supplement. Mean 25-OHD increased 16 to 49 nmol/L (TG) and 39 nmol/L to 67 nmol/L (RG), (both p < 0.001). Grip strength had improved from 153 to 188 N (TG) (p < 0.001) and from 257 to 297 N (RG) (p = 0.003) and inability to squat had decreased in TG (35 to 9, p < 0.001). Intake of number of tablets predicted increased grip strength (B 0.067, 95%CI 0.008-0.127, p = 0.027). One tablet daily (>300 in total) predicted improved ability to squat (OR 16; 95% CI 1.8-144.6).
  
  
  
  Adherence to supplemental vitamin D and calcium should be encouraged as an even moderate intake was associated to improved grip strength and upper leg performance, which was particularly useful for the women with severe 25-OHD deficiency and poor physical performance at baseline.
  
  
  
  ClinicalTrials.gov Identifier: NCT02922803 . Date of registration: September 28, 2016.
authors.affiliation: Primary Health Care Centre Jakobsgårdarna, Jaxtorget 7A, Box 100 33, S-781 10, Borlänge, Sweden. paul.kalliokoski@ltdalarna.se.|Centre for Clinical Research Dalarna, Falun, Sweden. paul.kalliokoski@ltdalarna.se.|Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden. paul.kalliokoski@ltdalarna.se.
authors.forename: Paul
authors.initials: P
authors.lastname: Kalliokoski
authors.affiliation: Centre for Clinical Research Dalarna, Falun, Sweden.|Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden.
authors.forename: Nils
authors.initials: N
authors.lastname: Rodhe
authors.affiliation: Centre for Clinical Research Dalarna, Falun, Sweden.
authors.forename: Yngve
authors.initials: Y
authors.lastname: Bergqvist
authors.affiliation: Uppsala University and Centre for Clinical Research Västmanland, Västerås, Sweden.|Division of Family Medicine, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.|Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden.
authors.forename: Monica
authors.initials: M
authors.lastname: Löfvander
mesh_terms: D000328:Adult; D002136:Calcium, Dietary / Q000627:therapeutic use; D002762:Cholecalciferol / Q000627:therapeutic use*; D065187:Controlled Before-After Studies; D003430:Cross-Sectional Studies; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007866:Leg / Q000503:physiopathology; D010349:Patient Compliance / Q000208:ethnology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy; D012621:Seasons; D012998:Somalia / Q000208:ethnology; D013548:Sweden / Q000208:ethnology; D013997:Time Factors; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy; D014815:Vitamins / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D002136:Calcium, Dietary; D014815:Vitamins; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D
keywords: Adherence; Grip strength; Multicultural care; Physical performance; Pregnancy; Somalia; Vitamin D