The Study On The Relation Between Serum Calcium And Serum Lipids And Serum Glucose In Urban Schoolchildren

Objective: This study was designed to analyse the relation betweenserum Calcium (Ca) and serum triglycerides (TG), total cholesterol (Tc),high-density lipoprotein cholesterol (HDL-c) and glucose through urbanschoolchildren in Shijiazhuang. It revealed the effect of serum calciumfluctuation on serum lipids and glucose metabolism disorder. This study canprovide scientific basis for prevention of children serum lipids and glucoseabnormality, and reduce the risk factor of cardiovascular disease such ashyperlipidemia and hyperglycaemia.Methods: Schoolchildren aged from7to13years old were selected bystratified cluster random sampling in Shijiazhuang city of Hebei Province.Height and body weight were measured, Body Mass Index (BMI) werecalculated. Serum calcium and serum TG, Tc, HDL-c, and glucose were tested.The difference of serum Ca among age-sex groups was compared by one-wayANOVA. The difference of serum TG, Tc, HDL-c and glucose among agegroups, sex groups and serum Ca decile groups was compared by covarianceanalysis, adjusting BMI, age and sex. The q test (SNK law) was choosen forthe multiple comparisons. The relevance between serum Ca and serum lipidsand glucose indexes were analysed using partial correlation analysis.According to the judging standard recommended by National CholesterolEducation Program (NCEP) and International Diabetes Federation (IDF), wecalculated abnormal rate of TG, Tc, HDL-c and glucose in each serum Cadecile group. The variation tendencies of abnormal rate was analysed by lineartrend test of chi-square test. We calculated the odd ratio (OR) and95%confidence interval. Non-conditional Logistic regression was used to analysethe abnormal rate and the risk of blood lipids and glucose, when the serum Carise or decline. The data were statistically analyzed using Statistical Package for the Social Sciences (SPSS). The difference was statistically significantwhen P＜0.05.Results:1Significant differences existed among age groups for Ca, TG, Tc,HDL-c and glucose. Following the index trend among the different age groups:①Serum Ca: The total average was2.11±0.28mmol/L. The serum Ca levelincreased with age increasing, except the10year-old group. The values of7-9year-old groups were higher than the10-13groups’, the value of11groupwas higher than12and13group.②Serum TG: TG decreased with ageincreasing in girls and total. In boys, TG level increased with age increasingexcept individual groups; TG swooped after11years old both in boys andgirls. Girls’ total average TG was significantly higher than boys’.③SerumTc: The Tc value decreased with age increasing. The value of7-9groups werehigher than11-13groups, the value of10year-old group was higher than12and13group.④Serum HDL-c: HDL-c value decreased from age7to10intotal, pick up in11and12-year-old groups, then declined to just a little over10age group level in13age group. The trends in boys and girls were similar.Boys’ total average HDL-c was significantly higher than girls’.⑤Serumglucose: Clucose value raised from age8to12in total and girls, and the valuein13group decreased suddenly. Glucose value continued rising from age8to13in boys. When the girls were11years old, the serum glucose increasedsignificantly early than boys in12year-old group.2There were significant differences of TG, Tc, HDL-c among serum Cadecile groups. From the2ndto the7thor8thCa decile groups, TG and Tcdecreased roughly. The results of multiple comparisons showed that the TGvalue in the2ndserum Ca decile group was significantly higher than the othergroups and the value of the7thserum Ca decile group was significantly lowerthan the1st~5th,9thand10thgroups in total. In girls and total, the Tc value inthe1stand2ndserum Ca decile group were significantly higher than the othergroups. In boys, Tc value in the1stserum Ca decile group was significantlyhigher than the4th~9thgroups and the2ndgroup was significantly higher than 3rd~10thgroups. In the first6Ca decile groups, HDL-c decreased roughly. TheHDL-c value in the1st~2ndserum Ca decile groups were significantly higherthan else groups. The results of partial correlation coefficient suggested thatserum Ca was negatively correlated with TG (r=-0.189), Tc (r=-0.261),HDL-c (r=-0.331). The results of chi-square test for liner trend test revealedthat the abnormal rate of TG (only in total) and Tc (in boys, girls and in total)decreased with serum Ca level increasing. The trend of HDL-c abnormalrate was none. The risk of abnormal rate of TG in the2ndCa decile group andTc in the1st,2ndand3rdgroups increased. The OR value were6.322,21.741,27.676and25.582.3There was no significant difference of glucose among serum Ca decilegroups by analysis of covariance and multiple comparisons. We only foundthat glucose value rise gentally from the1stto the8thCa decile group. Theresults of partial correlation coefficient suggested that serum Ca was positivecorrelated with glucose, r=0.104. The results of chi-square test for liner trendtest revealed that the abnormal rate of glucose (in boys, girls and in total)increased with serum Ca level increasing. The abnormal rate of glucose in the8thCa decile group increased, OR=3.859.Conclusions:1The indexes’ trends of schoolchildren: The value of serum Ca andglucose increased substantially with age increasing. TG, Tc and HDL-cdecreased substantially with age increasing. Girls’ TG was significantlyhigher than boys’, boys’ HDL-c was significantly higher than girls’.2Among different serum Ca decile groups, there were significantdifferences of TG, Tc and HDL-c, and no significant difference of glucose.Serum Ca was negatively correlated with TG and Tc, and the abnormal rate ofthem decreased with serum Ca level increasing. Serum Ca was negativelycorrelated with HDL-c. We’ve found no significant trend of HDL-c abnormalrate. Serum Ca was positive correlated with glucose, while the abnormal rateof glucose increased with serum Ca level increasing. When the serum Ca waslower, the risk of TG and Tc abnormal rate increased. The risk of glucose abnormal rate increased when the serum Ca was higher. Whether the serumCa was high or low, the HDL-c abnormal rate didn’t increase.In summary, serum Ca was negatively correlated with TG and Tc. Therisk of TG and Tc abnormal rate raised when the serum Ca was lower. Theserum Ca was also negatively correlated with HDL-c. However the HDL-cabnormal rate didn’t increase. Serum Ca was positively correlated withglucose, and the abnormal rate of glucose raised when the serum Ca level washigher. Our results reveal the relationship between serum Ca and themetabolism of serum lipids and glucose was complex. It may be beneficial forthe prevention of hyperlipidemia and hyperglycaemia that the serum Ca levelis normal and reasonable.