Passive smoking and behavioural problems in children: results from the LISAplus prospective birth cohort study.

OBJECTIVE: To analyse the association between pre- and postnatal exposure to tobacco smoke and child behavioural problems and to further investigate the influence of trimester-specific exposure to maternal smoking and the impact of paternal smoking at home on the same outcome. METHODS: Data of 3097 German children recruited at birth for a population-based, prospective study were used. Detailed information on children's tobacco smoke exposure was collected by self-administered questionnaires at each follow-up. Behavioural outcomes were measured by the Strengths and Difficulties Questionnaire applied at 10-year follow-up. RESULTS: Children exposed to environmental tobacco smoke at home showed increased risks of hyperactivity/inattention problems. Only smoking during the entire pregnancy increased the risk for conduct and hyperactivity/inattention problems (proportional odds ratio (pOR)=1.58, 95% confidence interval (CI)=1.06-2.37 and pOR=1.67, CI=1.03-2.72). Pre- and postnatal exposure to paternal smoking was associated with hyperactivity/inattention problems in children of non-smoking mothers (pOR=1.97, CI=1.06-3.65). Effect estimates were adjusted for study centre, sex, parental educational level, mother's age at birth, having a single parent and time spent in front of a screen. CONCLUSIONS: Not only maternal smoking during pregnancy but also paternal smoking at home should be considered as a risk for hyperactivity/inattention problems in children.

Prenatal and postnatal tobacco smoke exposure and development of insulin resistance in 10 year old children.

In this study, we evaluated the association between prenatal and postnatal exposure to environmental tobacco smoke and the development of insulin resistance in 10 year old children. Fasting blood samples were collected from 470 children participating in two prospective birth cohorts. Of those 276 were selected population based and enriched with 194 children exceeding the 85th percentile of body mass index in this age group. Children already having diabetes type 1 or 2 at the age of 10 years were excluded. Fasting blood insulin and glucose levels and calculated HOMA index for insulin resistance assessment were analysed using generalised additive models. Potential confounders were adjusted for. Insulin resistance was increased by 24% in children frequently exposed to environmental tobacco smoke during childhood (MR(adj) = 1.24, p = 0.001), while glucose levels were not. Exclusion of prenatally exposed children did not attenuate the association (MR(adj) = 1.25, p = 0.006). After stratification, the effect sizes were identical within overweight children and the population based sample of children. Insulin resistance and fasting insulin levels were increasing with increasing numbers of cigarettes smoked in children's home. Maternal smoking during the third trimester of pregnancy increased children's insulin levels (MR(adj) = 1.19, p = 0.037), and even more so, if children were exclusively breastfed after birth (MR(adj) = 1.31, p = 0.016). Increased mean ratios were found for smoking of a third person in addition to maternal smoking. Positive dose-dependent associations and independent effects of postnatal exposure suggest involvement of environmental tobacco smoke in the risk for development of insulin resistance in children.

Growth of infants fed formula rich in canola oil (low erucic acid rapeseed oil).

BACKGROUND & AIMS: Canola oil is a variety of rapeseed oil low in erucic acid (<2%). For many years, canola oil has been widely used as an ingredient in infant formula in Europe, but not in North America due to safety concerns. A number of studies have used variable canola content of infant formulas to investigate the effects of linoleic acid: α-linolenic acid ratio on visual function of infants. However, little published data is available to compare the safety of canola versus non-canola containing infant formula. The aim of this study is to investigate whether infant formulas containing canola oil support normal growth in infants as assessed by weight and length gain. METHODS: Re-analyses of data on infant weight and length gain from a prospective randomized double-blind trial in full-term infants in the German Infant Nutritional Intervention study (GINI). This analysis compared growth in infants receiving infant formulas with or without canola oil from week 4 to month 7. Absolute weight and length, weight and length gain in gram or cm per day and standardized weight and length measurements were analyzed by analyses of variance and a longitudinal random effects model. Standardization was conducted according to the new WHO 2006 age- and sex-specific child growth standards. RESULTS: Absolute and standardized weight and length measures did not differ between the formula groups with or without canola oil. This was true for both, analyses within each of the three anthropometric measurement periods (4-6 weeks, 3-4 months, 6-7 months) and for the longitudinal analyses over the whole period from 4 weeks to 7 months of life. Power analyses confirmed that sample size was sufficient to detect a difference of 3 g per day between 14 and 120 days between the two formula groups. CONCLUSIONS: Infant formula containing canola oil supports normal infant growth as assessed by weight and length gain.

Maternal fine particulate matter exposure, polymorphism in xenobiotic-metabolizing genes and offspring birth weight.

We aimed to describe if polymorphisms in xenobiotics-metabolizing genes modify the effect of maternal exposure to fine particulate matter (PM(2.5)) on offspring birth weight. Among newborns from LISA cohort, we tested if polymorphisms of GSTT1, GSTP1, GSTM1, and CYP2D6 genes modified the effect measure of PM(2.5) on term birth weight. Subsequently, we tested if polymorphisms modified the effect of other exposure factors with possibly similar pathways of action (active or passive smoking). PM (2.5) exposure above the median value (reference, below) was associated with birth weight changes by 76 g in the homozygous wild type genotype (n=161), -90 g in the heterozygous genotype (n=154) and -168 g in children with GSTP1 *1B/*1B mutant genotype (n=39, interaction test, p=0.05). No effect measure modification with PM(2.5) was detected for GSTT1, GSTM1 or CYP2D6 polymorphisms (p≥ 0.12). No effect measure modification with GSTP1 polymorphism was detected for active (p=0.71) nor for passive smoking effects on birth weight (p=0.13).

Prenatal and postnatal tobacco exposure and behavioral problems in 10-year-old children: results from the GINI-plus prospective birth cohort study.

BACKGROUND: Prenatal and postnatal tobacco exposure have been reported to be associated with behavioral problems. However, the magnitude of the association with tobacco exposure at specific periods of exposure is unclear. OBJECTIVE: We assessed the relative risk of behavioral problems in children who had been exposed to tobacco smoke in utero and postnatally. METHODS: We analyzed data from a prospective birth cohort study in two cities in Germany: the German Infant Nutrition Intervention. Our sample included 5,991 children born between 1995 and 1998 as well as their parents. We measured behavioral problems using the Strength and Difficulties Questionnaire (SDQ) at follow-up 10 years after birth. According to prespecified SDQ cutoff values, children were classified as "normal," "borderline," or "abnormal" according to the subscales "emotional symptoms," "conduct problems," "hyperactivity/inattention," "peer-relationship problems," and a total difficulties score. Smoke exposure and further covariates were assessed using parent questionnaires. RESULTS: Compared with children not exposed to tobacco smoke, children exposed both pre- and postnatally to tobacco smoke had twice the estimated risk [95% confidence interval (CI), 1.4-3.1] of being classified as abnormal according to the total difficulties score of the SDQ at 10 years of age. Children who were only prenatally exposed had a 90% higher relative risk (95% CI, 0.9-4.0), whereas children who were only postnatally exposed had a 30% higher relative risk (95% CI, 0.9-1.9). These results could not be explained by confounding by parental education, father's employment, child's time spent in front of computer or television screen, being a single father or mother, or mother's age. CONCLUSIONS: Prenatal exposure to tobacco smoke is associated with behavioral problems in school-age children. Although our findings do not preclude the influence of postnatal exposure, prenatal exposure seems to be more important.

A new FFQ designed to measure the intake of fatty acids and antioxidants in children.

OBJECTIVE: The present paper describes the systematic development of an FFQ to assess the intake of fatty acids and antioxidants in school-aged children. In addition, a validation study applying 24 h dietary recalls was performed. DESIGN: Using the variance-based Max_r method, a list of eighty-two foods was compiled from data obtained by 3 d weighed dietary records. The foods were used to design an FFQ, the comprehensibility of which was evaluated in a feasibility study. In addition, the FFQ was validated in a subset of 101 children from the German Infant Nutritional Intervention Study (GINI PLUS) against one 24 h dietary recall. RESULTS: The feasibility study attested a good acceptance of the FFQ. Mean intake of foods compared well between the FFQ and the 24 h dietary recall, although intake data generated from the FFQ tended to be higher. This difference became less apparent at the nutrient level, although the estimated average consumption of arachidonic acid and EPA using the FFQ still exceeded values recorded with the 24 h recall method by 45 % and 29 %, respectively. CONCLUSIONS: On the basis of the systematic selection process of the food list, the established practicability of the FFQ and the overall plausibility of the results, the use of this FFQ is justified in future epidemiological studies.

Period-specific growth, overweight and modification by breastfeeding in the GINI and LISA birth cohorts up to age 6 years.

Children's weight/growth development is age-specific and may be influenced by breastfeeding. We therefore assessed velocities of weight, length, body-mass-index and overweight/obesity development from birth up to age 6 years overall and in relation to breastfeeding. The method of this study is based on pooled data of the birth-cohorts GINI-plus and LISA-plus and follows 7,643 healthy full-term neonates in four study-centers in Germany. Up to nine anthropometric measurements are available. Overweight/obesity is percentile-defined according to WHO-Child-Growth-Standards. Fully-breastfed is defined as breastfed for at least 4 months. Piecewise-linear-random-coefficient-models were applied to assess growth trajectories and velocities between 0-3, 3-6, 6-12, 12-24 and beyond 24th months. Velocities for weight-, length- and BMI-development are highest in the first 3 months after birth and diminish, with differing pace, in the periods that follow. For overweight and obesity, peak-velocities are estimated in periods 6-12 and 3-6 months. The difference in the velocity of weight gain for breastfed vs. other children is -18 g/month in the first 3 month, -93 g/month between month 3 and 6, -14 g/month between month 6 and 12 and -3 g/month beyond the 24th month. Velocities in length are not different between breastfed and non-breastfed children. Over time, a slightly lower risk (difference < 2%) of being overweight was estimated for breastfed children, after adjustment for study-center, socio-economic-status and maternal smoking in pregnancy. Infants fully-breastfed gain less weight, but grow equally in length in the first 12 months of life versus mixed or formula-fed children. The protective effect of breastfeeding on becoming overweight is related to its weight-velocity-modifying-effect in early infancy.

Impact of parental education and income inequality on children's food intake.

OBJECTIVE: To analyse the association between socio-economic indicators and diet among 2-year-old children, by assessing the independent contribution of parental education and equivalent income to food intake. DESIGN: The analysis was based on data from a prospective birth cohort study. Information on diet was obtained using a semi-quantitative food-frequency questionnaire. Low and high intake of food was defined according to the lowest and the highest quintile of food consumption frequency, respectively. SETTING: Four German cities (Munich, Leipzig, Wesel, Bad Honnef), 1999-2001. Subjects Subjects were 2637 children at the age of 2 years, whose parents completed questionnaires gathering information on lifestyle factors, including parental socio-economic status, household consumption frequencies and children's diet. RESULTS: Both low parental education and low equivalent income were associated with a low intake of fresh fruit, cooked vegetables and olive oil, and a high intake of canned vegetables or fruit, margarine, mayonnaise and processed salad dressing in children. Children with a low intake of milk and cream, and a high intake of hardened vegetable fat, more likely had parents with lower education. Low butter intake was associated with low equivalent income only. CONCLUSIONS: These findings may be helpful for future intervention programmes with more targeted policies aiming at an improvement of children's diets.

Sodium intake and bronchial hyperresponsiveness in adults.

BACKGROUND: Several investigations suggested a relationship between sodium intake and asthma and bronchial hyperresponsiveness (BHR), respectively. However, clinical and epidemiological studies did not show consistent finding. OBJECTIVE: We analysed the association between dietary sodium intake and BHR to methacholine among 613 adults aged 20-65 years as one of the two German centres of the European Community Respiratory Health Survey (ECRHS). METHODS: Dietary sodium intake was estimated from a 3-day weighed record of food intake. We applied multiple logistic regression models contrasting the three higher quartiles of sodium intake versus the lowest to assess the risk of BHR and mild BHR estimated by PD20 and PD10, respectively, controlling for potential confounders and stratified for sex. In addition, we analysed PD20 (dose of methacholine causing a fall of 20% in forced expiratory volume in 1s) as continuous variable expressed as transformed dose-response slope (tDRS) in the linear model. RESULTS: Women were as expected more likely to be bronchial hyperresponsive (PD20: 26.1%; PD10: 52.2%) than men (PD20:15.8%; PD10: 34.8%) and had a lower mean daily sodium intake (2.36 g) compared with men (3.15 g). Logistic regression did not show any significant relationship between sodium intake and BHR in terms of PD20 after adjustment for age group, education, smoking status, body mass index and height in men or women. However, mild BHR assessed as PD10 was statistically significant positively related to the third (OR: 2.35; CI: 1.11-5.00) and highest quartile of sodium intake (OR: 2.28; CI: 1.06-4.88) in women, but not in men for third quartile (OR: 1.29; CI: 0.68-2.44) and for fourth quartile (OR: 1.07; CI: 0.56-2.07), respectively. CONCLUSION: Sodium intake by several food items does not alter BHR assessed as PD20 to methacholine but may increase mild BHR assessed as PD10. We conclude that, in addition, PD10 has to be considered when the effect of sodium intake on BHR is studied.