| ObjectiveTo analyze the effect of gender, age, and season on HbA1c, and to investigate theseasonal variation of glycosylated hemoglobin (HbA1c).MethodsSubjects included type2diabetic patients, according to1999WHO experts committeediagnosis standard, and with reference to the2010ADA diabetes diagnosis new guidelines,who regularly visited a single diabetic outpatient clinic in Jinan central hospital from2008to2011. The cohort study included560patients with2188A1c tests in2008,723patientswith2875A1c tests in2009,1065patients with4269A1c tests in2010, and1374patientswith5026A1c tests in2011. The data extracted from Hospital Information System (HIS)in Jinan Central Hospital from2008to2011was exported to Microsoft Excel2003database and analyzed to draw a statistical graph using a SPSS18.0software. Generalcharacteristics of subjects are summarized with means±SD for continuous data. One-wayANOVA and Univariate were used to test the effect of gender, age, and season on HbA1c.Independent-Samples T Test was used to test sexual difference in every age group.Multiple linear regression analysis was used to test whether gender, age and season wereassociated with HbA1c. For all results P<0.05was considered as significant difference.Results were given as means±1standard deviation.Results1. The HbA1c had significant seasonal variation (P <0.05), higher in winter fromDecember to February, lower in summer from June to August. There was a mean1.17%difference between the highest levels in winter and the lowest levels in summer. In2008,the maximum values were noted in the winter months of December and February(7.57±2.15,7.47±2.05, respectively), and lower values were observed in August(6.75±1.92). In2009and2010, the higher levels were noted in January and February, withlower values in August and September. In2011, the highest HbA1c value appeared in February and January(7.85±2.39、7.24±1.81, respectively), with lowest value inAugust(6.69±2.11).2. The distribution of HbA1c in the whole population is approximately normal. Therewere significant differences in HbA1c according to gender (P<0.05):7.21±1.80in men vs7.39±1.71in women in2008;7.46±2.10in men vs7.63±2.03in women in2009;7.12±1.91in men vs7.28±2.30in women in2010;7.04±1.98in men vs7.16±2.03inwomen in2011. Glycosylated hemoglobin in females were significantly higher than inmales with a maximum difference of0.18%. The results of Independent-Samples T Test ongender in each age group from2008to2011respectively showed that no significant sexdifference existed for HbA1c, except for the group over sixty, in which men had lowerlevels than women (P<0.01). In2008,2009and2011, the HbA1c level had significant agedifference in both sexes (P <0.05); After SNK-q and LSD-t tests, we found the HbA1cbetween the youth and the middle-aged was not significantly different, but bothsignificantly higher than that of the elderly. In2010, there was no obvious differenceamong each age group (P=0.136); but the levels of HbA1c in the youth and the middle-aged were still slightly higher than that of the elderly (the levels of the youth, the middle-aged and the elderly were7.23±0.16,7.29±0.06,7.14±0.05, respectively).3. Multiple linear regression analysis with HbA1c as the dependent variable showed thatgender, age and season were all factored into the regression equation, and had negativecorrelations with HbA1c (standardized regression coefficients=-0.050,-0.06,-0.040respectively; P<0.01).ConclusionThere was significant seasonal variation in HbA1c, higher in the cooler season, lowerin the warmer season. Temperature differences play a role in HbA1c values. Age,seasonand gender appeared as risk factors influencing HbA1c independently. |
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