title: Seasonal Pattern in the Diagnosis of Gestational Diabetes Mellitus in Southern Sweden.
abstract: Aim. The aim of this study was to examine seasonal patterns in glucose tolerance and in the diagnosis of gestational diabetes mellitus (GDM).Methods. Altogether, 11 538 women underwent a 75-g oral glucose tolerance test (OGTT) in the twenty-eighth week of pregnancy during the years 2003-2005 in southern Sweden. GDM was defined by the 2-h capillary glucose concentration in the OGTT (≥8.9 mmol/L). Chi-squared test, analysis of variance, and regression analyses were used for statistical evaluations.Results. The seasonal frequency of GDM ranged from 3.3% in spring to 5.5% in summer (p< 0.0001). Mean 2-h glucose concentrations followed the same seasonal trend, with a difference of 0.15 mmol/L between winter and summer (p< 0.0001). The 2-h glucose level increased by 0.009 mmol/L for every degree increase in temperature (p< 0.0001). In regression analysis, summer (June-August) was associated with increased 2-h glucose level (p< 0.001) and increased frequency of GDM compared to the other seasons (odds ratio 1.51, 95% confidence interval 1.24-1.83, andp< 0.001).Conclusions. Our findings suggest seasonal variation in the 2-h glucose concentration in the OGTT and in the proportion of women diagnosed with GDM, with a peak in the summer.
authors.affiliation: Department of Clinical Sciences, Lund University, Malmö, Sweden; Department of Endocrinology, Skåne University Hospital, Malmö, Sweden.
authors.forename: Anastasia
authors.identifier: 0000-0001-7747-5264
authors.initials: A
authors.lastname: Katsarou
authors.affiliation: Department of Clinical Sciences, Lund University, Malmö, Sweden; Department of Obstetrics and Gynaecology, Office for Healthcare "Kryh", Ystad, Sweden.
authors.forename: Rickard
authors.initials: R
authors.lastname: Claesson
authors.affiliation: Department of Clinical Sciences, Lund University, Malmö, Sweden; Department of Obstetrics and Gynaecology, Office for Healthcare "Sund", Helsingborg, Sweden.
authors.forename: Claes
authors.identifier: 0000-0001-7317-1861
authors.initials: C
authors.lastname: Ignell
authors.affiliation: Department of Clinical Sciences, Lund University, Malmö, Sweden; Department of Endocrinology, Skåne University Hospital, Malmö, Sweden.
authors.forename: Nael
authors.initials: N
authors.lastname: Shaat
authors.affiliation: Department of Clinical Sciences, Lund University, Malmö, Sweden; Department of Endocrinology, Skåne University Hospital, Malmö, Sweden.
authors.forename: Kerstin
authors.identifier: 0000-0002-5557-5085
authors.initials: K
authors.lastname: Berntorp
mesh_terms: D001786:Blood Glucose / Q000032:analysis*; D016640:Diabetes, Gestational / Q000175:diagnosis*; D005260:Female; D018149:Glucose Intolerance / Q000175:diagnosis*; D005951:Glucose Tolerance Test; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012621:Seasons; D013548:Sweden
chemical_list: D001786:Blood Glucose