| BackgroundAnemia and obesity are two of the most common nutritional disorders among Chinese population,and iron deficiency is considered to be the primary cause of anemia.Researchers have been thinking that iron deficiency is induced by under-nutrition and is more prevalent in infants,pregnant and feeding women, adolescent girls and elders,while the relation of overweight,obesity and iron deficiency has not been explored well.Researches on obesity and iron deficiency concluded different results,and few representative studies on obesity and iron deficiency was reported in China.ObjectiveTo assess status and the risk factors of iron deficiency and anemia in overweight and obesity populations,compared with normal weight population,using data of 2002 China National Nutrition and Health Survey.Relation between obestisy and iron deficiency was explored as well.MethodSample were from 2002 China National Nutrition and Health Survey,Analyses were limited to people aged 3 to 44 years old(129,191),in which pregnant and feeding women,as well as individuals without Hb values were excluded.Four groups were derided according to age,namely 3- to 5-year-old children(11945),6- to 11-year-old children(30413),12- to 17-year-old adolescents(17784) and 18- to 44-year-old adults(69049).Variables included demograpic features,body mass levels,anemia and iron deficiency status,dietary indexes and physical activity level.ANOVA,χ~2 test,pearson correlation,logsitic regression and factor analysis were used.Results1.Overweight and obesity:18- to 44-year-old adults demonstrated the highest prevalence of overweight(22.86%) and obesity(6.57%);12- to 17-year-old adolescents showed the lowest prevalence of overweight(4.44%) and obesity(2.08%);prevalence of overweight and obesity among 3- to 5-year-old children(8.88%,6.80%) and 6- to 11-year-old children(6.19%,4.38%) were at middle levels.Overweight and obesity were more prevalent in urban areas,population above poverty level,male individuals. Prevalence of abdominal obesity is 21.46%among adults,increasing with age.2.Iron status:Hb was found increasing with age,which was lower in boys than girls among 3- to 5-year-old children,however,higher in males than females among 12- to 17-year-old adolescents and 18- to 44-year-old adults.Anemia demonstrated the similar upward trend with age increase(10.32%,10.62%,15.92%,20.95%,respectively from children to adults).Females and rural individuals seemed to be at higher risk of anemia.Serum ferritin was higher in elder individuals.Urban children had lower serum ferritin level(43.71μg/L) than rural children(49.21μg/L);while urban adults had significantly higher serum ferritin level(86.04μg/L) than rural adults(81.77μg/L). Children either 3- to 5-year-old or 6- to 11-year-old demonstrated that girls had higher serum ferritin level than boys,while adolescents and adults implied that female had lower serum ferritin.The highest prevalence of iron deficiency defined by serum ferritin occurred in adults group(9.72%),the following groups were adolescents (4.94%),3- to 5-year-old children(3.95%),6- to 11-year-old children(2.96%).Boys of 3- to 5-year-old children had higher prevalence of iron deficiency than girls,while that of femal adolescents and adults were higer than males.The results suggested that growth need was the main risk factor for male iron deficiency,while catamenia, pregnant,feeding as well as growth were the risk factors for female iron deficiency. Iron deficiency rate in urban areas was lower than that in rural areas among adolescents and adults.3.Anamia and iron deficiency in different body mass levels:Overweight and obesity individuals demonstrated lower prevalence of anemia than underweight and normal weight groups.It was noticed that obesity children and adolescents were at higher risk for anemia than overweight children and adolescents. Though prevalence of anemia in adults decreased as BMI increased,we should also notice that overweight and obesity female adults had a high level of anemia.Prevalence of iron deficiency increased as BMI increase from underweight to normal weight to overweight and to obesity in 3- to 5-year-old children and girls in 6-to 17-year-old children and adolescents.The same trend wasn't found in adults and boys in 6- to 17-year-old children and adolescents.4.Correlation of obesity and iron status:There was a positive correlation between obesity and Hb value among all groups.Negative correlations were found in 3- to 5-year-old child and girls of 6- to 17-year-old children and adolescents.Logistic regression was used to estimate the independent association between iron status and obesity,control age,gender and area,made normal weight as control group.It was noted that overweight and obesity children aged 3 to 5 had a significantly increased risk of iron deficiency,with odds ratio at 1.50(1.09-2.05), 1.46(1.02-2.01),respectively,while a decreased risk for anemia,with odds ratio at 0.69(0.54-0.89),0.89(0.69-1.15),respectively.Overweight and obesity individuals had a lower risk for anemia among 6- to 11-year-old children,12- to 17-year-old adolescents and 18- to 44-year-old adults.Obesity adults had a decreased risk for iron deficiency with odds ratio at 0.81(0.67-0.98).Significant correlation wasn't found between obesity and iron status among other groups.5.Risk factors for anemia and iron deficiency in overweight and obesity population:Social-economic factors,such as rural area,income below poverty,low grade of education,female adolescents and adults were major risk factors for anemia and iron deficiency in overweight and obesity population.Growth retardation was a risk factor for anemia in 3- to 5-year-old children,with odds ratio at 2.93(1.98-4.35).Overweight and obesity adults with static life time≥5h/d or abdominal obesity had a decreased risk for anemia and iron deficiency.Dietary fators didn't account for the relation between obesity and iron deficiency.ConclusionsPrevalence of anemia and obesity were at high level among 3- to 44-year-old population in China.Rural individuals,younger children,female adolescents and adults were risk groups for anemia and iron deficiency.There was a positive correlation between obesity and Hb.In children and adolescent groups,obesity individuals had a higher prevalence of anemia than overweight ones,both of which were lower than underweight and normalweight children and adolescents.Among adults population,prevalence of anemia decreased from underweight to normalweight to overweight to obesity groups.Overweight and obesity groups of 3- to 5-year-old children and girls in 6- to 17-year-old children and adolescents were at higher risk for iron deficiency,compared with underweight and normalweight groups.The same trend wasn't found in adults and boys in 6- to 17-year-old children and adolescents.Social-economic factors accouted for anemia and iron deficiency in Chinese overweight and obesity population aged 3 to 44.Dietary effects in relation of obesity and iron status weren't supported sufficiently. |
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