Corrective lens wear among adolescents: findings from the National Health and Nutrition Examination Survey

PURPOSE: To evaluate demographic variations in the use of corrective lenses among adolescents. METHODS: Cross-sectional analysis of 3,916 adolescents between ages 12 and 18 years who participated in the 1999-2002 National Health and Nutrition Examination Survey (NHANES) vision examination component, which included questions regarding use of corrective lenses, distance visual acuity (VA; with corrective lenses if available), and non-cycloplegic autorefraction. Results reflect population-level estimates. RESULTS: Overall, 32.2% (95% confidence interval [CI], 29.5%-35.0%) reported wearing corrective lenses. The adjusted odds of reporting corrective lens wear were greater for female and privately insured participants. In contrast, the adjusted odds of having corrective lenses available at the time of NHANES participation were greater for participants between ages 15 and 18 years compared with those between 12 and 14 years, and participants who were white compared with those who were black or Hispanic. Although 12.6% (95% CI, 8.8%-16.3%) of participants without their corrective lenses available for the NHANES had 20/25 or better distance VA in both eyes, 26.9% (95% CI, 21.6%-32.1%) of those with their corrective lenses had distance VA of 20/40 or worse in at least 1 eye. Near VA was not measured and participants with their corrective lenses available had only their corrected distance VA measured. No data regarding the accuracy of the NHANES assessment of distance VA are available. Autorefraction was performed without cycloplegia. CONCLUSIONS: Many adolescents report wearing corrective lenses. Variations across demographic characteristics are possibly due to a combination of undertreatment, overtreatment, and compliance with previously recommended corrective lenses.     

Health effects related to environmental tobacco smoke exposure in children in the United States: data from the Third National Health and Nutrition Examination Survey

OBJECTIVE: To determine the effects of prenatal and postnatal smoke exposure on the respiratory health of children in the United States. DESIGN: Nationally representative cross-sectional survey, including questionnaire information, measurements of serum cotinine (a metabolite of nicotine), and pulmonary function measurement, of 5400 US children. SETTING AND PARTICIPANTS: Children aged 4 to 16 years in the Third National Health and Nutrition Examination Survey, October 25, 1988, to October 15, 1994. METHODS: We stratified the study participants into tertiles, on the basis of serum cotinine levels, and used logistic and linear regression modeling, adjusting for known covariates, to determine the effect of high environmental tobacco smoke (ETS) exposure (on the basis of a high cotinine level) on outcomes such as the prevalence of current asthma, the prevalence of frequent wheezing, school absence, and lung function. For children aged 4 to 11 years, we also determined the effect of prenatal maternal smoking on these outcomes. RESULTS: We observed effects of ETS exposure in all age groups, although the effects varied between age groups. Among all children significant effects associated with high cotinine levels were for wheezing apart from cold in the past year (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-2.8); 6 or more days of school absence in the past year (OR, 2.0; 95% CI, 1.4-2.8); and lung function decrements in the forced expiratory volume in 1 second (mean change, -1.8%; 95% CI, -3.2% to -0.4%) and the maximal midexpiratory flow (mean change, -5.9%; 95% CI, -8.1% to -3.4%). Although current and ever asthma were not significantly associated with high cotinine levels in the overall group (OR, 1.5; 95% CI, 0.8-2.7, and OR, 1.3; 95% CI, 0.8-2.2, respectively), they were increased significantly among 4- to 6-year-old children (OR, 5.3; 95% CI, 2.2-12.7, and OR, 2.3; 95% CI, 1.1-5.1, respectively). CONCLUSIONS: We investigated recent ETS exposures as important predictors of respiratory health outcomes in children 4 years and older. Environmental tobacco smoke exposure affects children of all ages, although the exact effects may vary between age groups.     

Relationship Between Low-Level Lead Exposure and Neurobehaviors of Preschool Children

目的　探讨低水平铅暴露对儿童神经行为的影响。方法　整群随机抽取某市幼儿园 4～ 6岁 2 11名儿童为研究对象 ,采指端末梢血 2 0 μl,原子吸收石墨炉法测定血铅 ,以血铅水平 10 0 μg/L为界 ,分为高血铅组(≥ 10 0 μg/L)和低血铅组 (<10 0 μg/L) ,采用Achenbach儿童行为量表 (CBCL)及自拟调查表进行问卷调查 ,其结果运用t ,χ2 检验 ,简相关及多元逐步回归等方法进行统计分析。结果　高血铅组外向行为得分及行为异常率(13.2 8± 6 .2 6 ,18.2 6 % )显著高于低血铅组 (9.98± 5 .4 6 ,7.2 9% ) (t =4 .0 6 77,χ2 =5 .4 70 ,均P <0 .0 5 ) ,血铅值与外向行为中多动、攻击、违纪因子分显著正相关 (r =0 .316 4 ,0 .2 82 8,0 .1886 ,P <0 .0 5 ) ,血铅值≥ 15 0 μg/L时 ,行为异常率显著增加 (χ2 =13.6 95 ,P <0 .0 5 )。结论　低水平铅暴露对儿童外向行为具有负性影响。     

Self-reported weight status and dieting in a cross-sectional sample of young adolescents: National Health and Nutrition Examination Survey III.

OBJECTIVE: To explore the relationship of self-reported weight status and dieting to actual weight and height in a cross-sectional nationally representative sample of young adolescents. METHODS: Weights and heights were obtained on 1932 adolescents aged 12 to 16 years enrolled in the National Health and Nutrition Examination Survey III. Information on adolescents' perception of weight status, desired weight, and weight loss attempts was obtained by questionnaire. RESULTS: Adolescents' reports of whether they considered themselves overweight or normal weight correlated poorly with medical definitions of overweight: 52% of girls who considered themselves overweight were, in fact, normal weight (body mass index < or = 85th percentile), while only 25% of boys who considered themselves overweight were normal weight (P<.001). Adolescent white girls were significantly more likely to consider themselves overweight, even when their weight status was normal, than black girls (P<.001), black boys (P<.001), and white boys (P<.001). Adolescent white girls were also more likely to diet than black girls (P<.001), black boys (P<.001), and white boys (P<.001). Dieting behavior was associated with whether adolescents viewed themselves as overweight independent of whether they actually were overweight. Racial differences between dieting and self-perceived weight status were limited to girls. There were no significant differences in self-perceived weight status (P = .28), dieting behaviors (P = .99), and desire to weigh less (P = .95) among black and white boys. CONCLUSIONS: Significant sex and racial differences existed in weight perception, desired weight, and dieting. A high proportion of normal-weight white girls consider themselves overweight and have attempted to lose weight.     

Blood lead levels and dietary calcium intake in 1- to 11-year-old children: the Second National Health and Nutrition Examination Survey, 1976 to 1980

Whether, and to what degree, dietary calcium is inversely associated with blood lead levels was examined in 2,926 black and white children, 1 to 11 years of age, from the Second National Health and Nutrition Examination Survey (NHANES II). Blood lead levels were significantly higher in black than in white children, whereas white children had significantly higher dietary calcium intake (P less than .0001). Using covariance analysis and multiple regression analysis, determinants of blood lead levels were assessed as follows. The dependent variable was log10 lead, with independent variables age, sex, race, height, Quetelet index, dietary intake of calcium, phosphorous, fat, carbohydrate, and calories, community size index, poverty index ratio, geographic region, urbanization index, and all two-way interactions of the preceding. In the multiple regression analysis, the following independent variables were significant, P less than .05. Race (black) and sex (male) were positively associated with blood lead level (P less than .0001 for both). The lower the family income and the more urban the family residence, the higher were the blood lead levels (P less than .0001, less than .008, respectively). A significant independent inverse association of blood lead levels with year of examination was noted, reflecting a downward secular trend in blood lead levels. Height was inversely associated with blood lead level (P less than .0001). Dietary calcium intake was also inversely associated with blood lead level (P = .028). Dietary intake of phosphorous, fat, carbohydrate, and total calories were not significantly associated with blood lead levels. The most direct strategy for prevention of childhood lead poisoning involves primary prevention to reduce exposure.(ABSTRACT TRUNCATED AT 250 WORDS)     

C-reactive protein and body mass index in children: findings from the Third National Health and Nutrition Examination Survey, 1988-1994

OBJECTIVES: To examine the relationship between C-reactive protein (CRP) concentration and body mass index (BMI) in children. STUDY DESIGN: With the use of data from 5305 children aged 6 to 18 years in the Third National Health and Nutrition Examination Survey (1988 to 1994), a cross-sectional health survey, we examined whether CRP concentrations were elevated among overweight children. RESULTS: Among children whose BMI was below the age- and sex-specific 15th percentile, 6.6% of boys and 10.7% of girls had an elevated CRP concentration (>2.1 mg/L) compared with 24.2% of boys and 31.9% of girls whose BMI was > or =95th percentile. After adjustment was done for age, sex, race or ethnicity, poverty income ratio, high-density lipoprotein cholesterol concentration, white blood cell count, and history of chronic bronchitis, the adjusted odds of having an elevated CRP concentration were 2.20 (95% CI 1.30, 3.75) for children with a BMI of 85th to <95th percentile and 4.92 (95% CI 3.39, 7.15) for children with a BMI of > or =95th percentile compared with children who had a BMI of 15th to <85th percentile. The associations did not differ significantly by age, sex, or race or ethnicity. CONCLUSIONS: In a large representative sample of US children, CRP concentration was significantly elevated among children with a BMI > or=85th percentile, thus confirming previous findings of this association in children and extending previous research in adults to children. Excess body weight may be associated with a state of chronic low-grade inflammation in children.     

Prevalence of diabetes and impaired fasting glucose levels among US adolescents: National Health and Nutrition Examination Survey, 1999-2002

OBJECTIVE: To determine the current prevalence of self-reported diabetes and impaired fasting glucose levels among US adolescents. DESIGN AND SETTING: Cross-sectional, National Health and Nutrition Examination Survey (1999-2002). PARTICIPANTS: A sample of 4370 adolescents (aged 12-19 years) with self-reported diabetes and a subsample of 1496 adolescents without self-reported diabetes who had fasted for at least 8 hours. Subjects who reported having diabetes and using insulin were further categorized as having type 1 diabetes, those reporting having diabetes and not using insulin as having type 2 diabetes, and those with a fasting plasma glucose level greater than or equal to 5.6 mmol/L (100 mg/dL) as having impaired fasting glucose levels. MAIN OUTCOME MEASURES: Prevalence of self-reported diabetes, type 1 and type 2 diabetes, and impaired fasting glucose levels among US adolescents. RESULTS: In the full sample, 0.5% (95% confidence interval [CI], 0.24%-0.76%) of adolescents reported having diabetes. Of those reporting diabetes, roughly 71% (95% CI, 56%-86%) were categorized as having type 1 and 29% (95% CI, 14%-44%) as having type 2 diabetes. In the subsample, roughly 11% (95% CI, 8%-14%) had impaired fasting glucose levels. Using population-based sample weights, these proportions were equivalent to 39 005 US adolescents with type 2 diabetes and 2 769 736 with impaired fasting glucose levels. CONCLUSIONS: The prevalence of type 2 diabetes and impaired fasting glucose levels is substantial among US adolescents. These estimates have important implications for public health because of the high rate of conversion from impaired fasting glucose level to type 2 diabetes in adults and the increased risk of cardiovascular disease in individuals with type 2 diabetes.     

Prevalence of a metabolic syndrome phenotype in adolescents: findings from the third National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND: In adults the metabolic syndrome imposes a substantial risk for type 2 diabetes mellitus and premature coronary heart disease. Even so, no national estimate is currently available of the prevalence of this syndrome in adolescents. OBJECTIVE: To estimate the prevalence and distribution of a metabolic syndrome among adolescents in the United States. DESIGN AND SETTING: Analyses of cross-sectional data obtained from the Third National Health and Nutrition Examination Survey (1988-1994), which was administered to a representative sample of the noninstitutionalized civilian population of the United States. PARTICIPANTS: Male and female respondents aged 12 to 19 years (n = 2430). MAIN OUTCOME MEASURES: The prevalence and distribution of a metabolic syndrome among US adolescents, using the National Cholesterol Education Program (Adult Treatment Panel III) definition modified for age. RESULTS: The overall prevalence of the metabolic syndrome among adolescents aged 12 to 19 years was 4.2%; 6.1% of males and 2.1% of females were affected (P=.01). The syndrome was present in 28.7% of overweight adolescents (body mass index [BMI], >/=95th percentile) compared with 6.8% of at-risk adolescents (BMI, 85th to <95th percentile) and 0.1% of those with a BMI below the 85th percentile (P<.001). Based on population-weighted estimates, approximately 910 000 US adolescents have the metabolic syndrome. CONCLUSIONS: Perhaps 4% of adolescents and nearly 30% of overweight adolescents in the United States meet these criteria for a metabolic syndrome, a constellation of metabolic derangements associated with obesity. These findings may have significant implications for both public health and clinical interventions directed at this high-risk group of mostly overweight young people.     

Cardiorespiratory fitness levels among US youth 12 to 19 years of age: findings from the 1999-2002 National Health and Nutrition Examination Survey

OBJECTIVES: To assess cardiorespiratory fitness levels in youth aged 12 to 19 years and to examine associations between fitness and age, sex, race/ethnicity, and self-reported physical activity in this age group. DESIGN: Cross-sectional study. SETTING: The National Health and Nutrition Examination Survey's mobile examination center, throughout the United States from 1999-2002. PARTICIPANTS: A representative sample of 4732 youth aged 12 to 19 years was examined; 3287 completed the treadmill test and were included in the analysis. The National Center for Health Statistics conducted the survey.Main Exposures Age, sex, race/ethnicity, weight status, self-reported physical activity, and television viewing.Main Outcome Measure Estimated maximal oxygen uptake (VO2max) determined by a submaximal treadmill exercise test. RESULTS: Estimated VO2max (mL.kg(-1) . min(-1)) was higher in males (mean +/- SE, 46.4 +/- 0.4) than in females (mean +/- SE, 38.7 +/- 0.3) but did not differ across race/ethnicity groups. Among males, older participants had higher VO2max values, while in females, younger participants had higher values. For both males and females, those in the normal weight group had higher fitness levels than those in the at risk for overweight and overweight groups. Approximately one third of both males and females failed to meet recommended standards for cardiorespiratory fitness. CONCLUSIONS: In US youth, cardiorespiratory fitness is lower in males and females who are overweight than in those of normal weight, but fitness is not related to race/ethnicity. Youth who have low levels of physical activity and high levels of sedentary behavior are also more likely to have lower cardiorespiratory fitness.     

Identification of population subgroups of children and adolescents with high asthma prevalence: findings from the Third National Health and Nutrition Examination Survey

OBJECTIVES: To provide national estimates of asthma prevalence in African-American, Mexican American and white (non-Latino) children and adolescents using several common definitions; to evaluate familial, sociodemographic, and environmental risk factors that are independently associated with current asthma in children; and to identify subgroups at particular risk for current asthma using 2 complementary data analytic approaches. DESIGN: Cross-sectional study, using the Third National Health and Nutrition Examination Survey, 1988-1994. SETTING: Eighty-nine mobile examination centers in the United States. PARTICIPANTS: Twelve thousand three hundred eighty-eight African American, Mexican American, and white (non-Latino) children and adolescents, aged 2 months through 16 years, selected from a systematic random, population-based, nationally representative sample. MAIN OUTCOME MEASURE: Current asthma, defined by caregivers who reported that their child currently had doctor-diagnosed asthma. RESULTS: The overall prevalence of current asthma was 6.7% (95% confidence interval [CI], 5.6-7.8). Odds ratios for current asthma from the multiple regression analysis were 4.00 (95% CI, 2.90-5.52) for children with a parental history of asthma or hay fever, 1.94 (95% CI, 1.09-3.46) for children with body mass index (calculated as weight in kilograms divided by the square of height in meters) greater than or equal to the 85th percentile, and 1.64 (95% CI, 1.20-2.26) for children of African American ethnicity. African American and Mexican American children showed a consistent prevalence of current asthma across age while white children showed an increase in prevalence with age. The 2 highest-risk subgroups identified by the signal detection analysis were composed of children with a parental history of asthma or hay fever who were 10 years or older with a body mass index greater than or equal to the 85th percentile (31.0% current asthma), and children with a parental history who were 10 years or younger and of African American ethnicity (15.6% current asthma). CONCLUSIONS: The findings from this analysis show a strong independent association between obesity and current asthma in children and adolescents, and confirm previous reports of a parental history of asthma or hay fever and African American ethnicity as additional important risk factors.     

Blood lead concentration and children's anthropometric dimensions in the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994

OBJECTIVE: To assess the association between lead exposure and children's physical growth. DESIGN: Cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey, 1988-1994. PARTICIPANTS: A total of 4391 non-Hispanic white, non-Hispanic black, and Mexican-American children age 1 to 7 years. Measurements and Results: We investigated the association between blood lead concentration and stature, head circumference, weight, and body mass index with multiple regression analysis adjusting for sex, ethnic group, iron status, dietary intake, medical history, sociodemographic factors, and household characteristics. Blood lead concentration was significantly negatively associated with stature and head circumference. Regression models predicted reductions of 1. 57 cm in stature and 0.52 cm in head circumference for each 0.48 micromol/L (10 micrograms/dL) increase in blood lead concentration. We did not find significant associations between blood lead concentration and weight or body mass index. CONCLUSIONS: The significant negative associations between blood lead concentration and stature and head circumference among children age 1 through 7 years, similar in magnitude to those reported for the Second National Health and Nutrition Examination Survey, 1976-1980, suggest that although mean blood lead concentrations of children have been declining in the United States for 2 decades, lead exposure may continue to affect the growth of some children.     

低水平铅暴露与儿童神经行为发育

本文主要从孕期铅暴露对婴儿神经行为发育的影响和儿童铅暴露有无安全界限两大研究热点对低水平铅暴露与儿童神经行为发育的关系进行综述,一方面强调了孕期铅暴露防治的重要性,另一方面指出由于无证据证明在血铅水平与认知功能之间存在安全界限,因此有必要重新审视CDC和WHO所警示的铅中毒界限,同时对儿童铅中毒的防治提出前瞻性设想。     

Television watching, energy intake, and obesity in US children: results from the third National Health and Nutrition Examination Survey, 1988-1994

OBJECTIVES: To examine the relationship between television watching, energy intake, physical activity, and obesity status in US boys and girls, aged 8 to 16 years. METHODS: We used a nationally representative cross-sectional survey with an in-person interview and a medical examination, which included measurements of height and weight, daily hours of television watching, weekly participation in physical activity, and a dietary interview. Between 1988 and 1994, the Third National Health and Nutrition Examination Survey collected data on 4069 children. Mexican Americans and non-Hispanic blacks were oversampled to produce reliable estimates for these groups. RESULTS: The prevalence of obesity is lowest among children watching 1 or fewer hours of television a day, and highest among those watching 4 or more hours of television a day. Girls engaged in less physical activity and consumed fewer joules per day than boys. A higher percentage of non-Hispanic white boys reported participating in physical activity 5 or more times per week than any other race/ethnic and sex group. Television watching was positively associated with obesity among girls, even after controlling for age, race/ethnicity, family income, weekly physical activity, and energy intake. CONCLUSIONS: As the prevalence of overweight increases, the need to reduce sedentary behaviors and to promote a more active lifestyle becomes essential. Clinicians and public health interventionists should encourage active lifestyles to balance the energy intake of children.