Lower levels of plasma 25-hydroxyvitamin D among young adults at diagnosis of autoimmune type 1 diabetes compared with control subjects: results from the nationwide Diabetes Incidence Study in Sweden (DISS).
OBJECTIVE
Low plasma vitamin D concentrations may promote the development of type 1 diabetes. To test this hypothesis, we measured plasma 25-hydroxyvitamin D (25OHD) in young adults with type 1 diabetes.


METHODS
The nationwide Diabetes Incidence Study in Sweden (DISS) covers 15- to 34-year-old people with newly diagnosed diabetes. Blood samples at diagnosis were collected during the 2-year period 1987/1988. Patients with islet antibodies (islet cell antibodies, GAD antibodies or tyrosine phosphatase-like protein antibodies) were defined as having autoimmune type 1 diabetes. Plasma 25OHD was measured in samples taken from 459 patients at the time of diagnosis, and in 138 of these subjects 8 years later. The results were compared with age- and sex-matched control subjects (n=208).


RESULTS
At diagnosis, plasma 25OHD levels were significantly lower in patients with type 1 diabetes than in control subjects (82.5+/-1.3 vs 96.7+/-2.0 nmol/l; p<0.0001). Eight years later, plasma 25OHD had decreased in patients (81.5+/-2.6 nmol/l; p=0.04). Plasma 25OHD levels were significantly lower in diabetic men than in diabetic women at diagnosis (77.9+/-1.4 vs 90.1+/-2.4 nmol/l; p<0.0001) and at follow-up (77.1+/-2.8 nmol/l vs 87.2+/-4.5 nmol/l; p=0.048).


CONCLUSIONS
The plasma 25OHD level was lower at diagnosis of autoimmune type 1 diabetes than in control subjects, and may have a role in the development of type 1 diabetes. Plasma 25OHD levels were lower in men than in women with type 1 diabetes. This difference may be relevant to the high incidence of type 1 diabetes among young adult men.
Littorin
B
B
Department of Clinical Sciences, University of Lund, Malmö University Hospital, Malmö, Sweden. bengt.littorin@med.lu.se
Blom
P
P
Schölin
A
A
Arnqvist
H J
HJ
Blohmé
G
G
Bolinder
J
J
Ekbom-Schnell
A
A
Eriksson
J W
JW
Gudbjörnsdottir
S
S
Nyström
L
L
Ostman
J
J
Sundkvist
G
G
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D012016:Reference Values; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
D014807:Vitamin D; C104450:25-hydroxyvitamin D