[Suspected adverse reactions after vaccination. Results from the German Health Interview and Examination Survey for Children and Adolescents. Part I: descriptive analyses]

The decreasing incidence of vaccine-preventable infectious diseases and their complications redirects public attention to the safety risks of vaccinations. Collation of resilient vaccine adverse reaction data from passive and active surveillance systems as well as epidemiological studies is indispensable. From 2003-2006, the representative National Health Interview and Examination Survey for Children and Adolescents ("Kinder- und Jugendgesundheitssurvey," KiGGS) retrospectively collected information about vaccines, vaccination dates, and suspected vaccine-related adverse events. A total of 15,958 participants (<17 years of age) were included in the analyses. Parents of 332 (2.1%; 95% CI 1.8-2.5) children and adolescents reported that one or more vaccinations were poorly tolerated. The reported adverse reactions were largely in accordance with information given in the summaries of product characteristics of the respective vaccines. Calculated rates of adverse reactions were below the known rates. KiGGS allowed the retrospective collection of suspected adverse reactions from a large number of vaccinations, thereby providing data even on rare adverse events. No unusual pattern was observed. The information obtained on suspected adverse reactions does not change the positive benefit-risk ratio of vaccinations.

Vaccination status and health in children and adolescents: findings of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)

BACKGROUND

Whether unvaccinated children and adolescents differ from those vaccinated in terms of health is subject to some discussion.

METHOD

We evaluated data on diseases that are preventable by vaccination, infectious and atopic diseases, and vaccinations received that had been collected between 2003 and 2006 in a representative sample of 17 641 subjects aged 0 to 17 years in the framework of the German Health Interview and Examination Survey for Children and Adolescents (Kinder- und Jugendgesundheitssurvey, KiGGS).

RESULTS

Evaluable data on vaccinations were available for 13 453 subjects aged 1-17 years from non-immigrant families. 0.7% of them (95% confidence interval: 0.5%-0.9%) were not vaccinated. The lifetime prevalence of diseases preventable by vaccination was markedly higher in unvaccinated than in vaccinated subjects. Unvaccinated children aged 1-5 years had a median number of 3.3 (2.1-4.6) infectious diseases in the past year, compared to 4.2 (4.1-4.4) in vaccinated children. Among 11- to 17-year-olds, the corresponding figures were 1.9 (1.0-2.8) (unvaccinated) versus 2.2 (2.1-2.3) (vaccinated). The lifetime prevalence of at least one atopic disease among 1- to 5-year-olds was 12.6% (5.0%-28.3%) in unvaccinated children and 15.0% (13.6%-16.4%) in vaccinated children. In older children, atopy was more common, but its prevalence was not found to depend on vaccination status: among 6- to 10-year-olds, the prevalence figures were 30.1% (12.9%-55.8%) for unvaccinated children versus 24.4% (22.8%-26.0%) for vaccinated children, and the corresponding figures for 11- to 17-year-olds were 20.3% (10.1%-36.6%) versus 29.9% (28.4%-31.5%).

CONCLUSION

The prevalence of allergic diseases and non-specific infections in children and adolescents was not found to depend on vaccination status.

Effects of latex avoidance on latex sensitization, atopy and allergic diseases in patients with spina bifida

BACKGROUND

Ten years ago, avoidance measures such as the performance of latex-free operations were implemented in children with spina bifida. Since then, latex sensitization and latex allergy have decreased in this high-risk group.

OBJECTIVE

To study the effect of primary latex-free prophylaxis on the prevalence of allergic diseases and atopy as a marker for sensitization spreading in children with spina bifida.

METHODS

One hundred and twenty children with spina bifida born after the introduction of latex-free prophylaxis and operated on under latex-free conditions ('current group') were examined for latex sensitization, latex allergy, sensitization to aero- and food allergens and allergic diseases. Results were compared to a 'historic' (not latex-free operated) group of children with spina bifida and comparable age (n = 87) and to a recent sample of children from the general population (n = 12,403).

RESULTS

In comparison with the 'historic group', latex sensitization (55% vs 5%, P < 0.001) and latex allergy (37% vs 0.8%, P < 0.001) were significantly reduced in the 'current group'. Furthermore, a significant reduction could be demonstrated for sensitization to aeroallergens (41.4% vs 20.8%, P = 0.001) and for allergic diseases (35% vs 15%, P = 0.001). The prevalence for atopy, sensitization to aero-/foodallergens and for allergic diseases in children of the 'current group' was similar to those in children of the weighted population sample.

CONCLUSIONS

Latex avoidance in children with spina bifida prevents latex sensitization and latex allergy. Additionally, it also seems to prevent sensitization to other allergens and allergic diseases which might be explained by the prevention of sensitization spreading.

Detection of respiratory events using pulse rate in children with and without obstructive sleep apnea

Oximetry is a simple but insensitive diagnostic test modality for obstructive sleep apnea (OSA) in children. Sensitivity for OSA may be enhanced if pulse rate is analyzed in conjunction with oxygen saturation. We analyzed 25 ambulatory polysomnographic recordings obtained from children with (n = 5) and without (n = 20) OSA. To assess sensitivity and specificity, pulse rate increases were determined during respiratory (i.e., apneas and hypopneas; n = 965) and non-respiratory sleep events (i.e., body movements; n = 1,197), and contrasted to baseline fluctuations (n = 209). The absolute pulse rate increase (APRI) was the parameter that differentiated best between baseline fluctuations and sleep events (area under the receiver operating characteristic curve [AUC]: 0.88). At a cutoff value of 12 beats per minute, APRI showed a sensitivity and specificity for detecting sleep events of 0.81 each. However, AUC was lower for the differentiation between respiratory and non-respiratory sleep events (0.77) and between central and obstructive respiratory events (0.68). In OSA cases, influencing factors for APRI following respiratory events were age, occurrence of a body movement, and severity of concomitant oxygen desaturation. We conclude that pulse rate analysis may be used to detect respiratory events in oximetry recordings in children.

Risk factors and consequences of excessive autonomic activation during sleep in children

PURPOSE

The aim of this study was to assess risk factors for excessive autonomic activation during sleep (EAAS) and its association with sleep problems, impaired behavior, and poor academic performance in primary school children.

METHODS

Data from a community-based study on 997 primary school children were used. Based on nocturnal home pulse oximetry, autonomic activation during sleep was defined as a pulse rate increase by more than 20%. Children with ≥35.9 autonomic activations per hour (i.e., ≥ the 95(th) centile) were classified as suffering from EAAS and compared with controls. Sleep problems, impaired behavior, and academic performance were assessed by parental questionnaires and analysis of school reports.

RESULTS

According to the above-mentioned definition, EAAS was diagnosed in 52 children (67% male). Risk factors for EAAS were male gender (odds ratio [95% confidence interval]: 2.06 [1.14-3.72]) and presence of symptoms of sleep-disordered breathing (3.48 [1.29-9.43]). Children with EAAS had a higher prevalence of hyperactive behavior (39.2% vs. 26.0%; p = 0.05) and enuresis (5.8% vs. 0.8%; p = 0.017) but not of poor academic performance. The association with hyperactive behavior was confirmed in a subsample (n = 119) using the Strengths and Difficulties Questionnaire. Mean (SD) score of the hyperactive-inattentive scale was 4.5 (2.8) for EAAS and 3.4 (2.7) for non-EAAS (p = 0.04).

CONCLUSION

EAAS may be a marker of sleep disruption in children and may predict the occurrence of enuresis and hyperactive behavior.

Population prevalence of obstructive sleep apnoea in a community of German third graders

We aimed to estimate the population prevalence of obstructive sleep apnoea (OSA) in an urban community of German third graders (age range 7.3-12.4 yrs) and the diagnostic test accuracy of two OSA screening methods. Using a cross-sectional study design with a multi-stage sampling strategy, 27 out of 59 primary schools within the city limits of Hanover, Germany, were selected. 1,144 third graders were screened for symptoms and signs of OSA using questionnaires and nocturnal home pulse oximetry. 183 children underwent abbreviated nocturnal home polysomnography (OSA definition: apnoea/hypopnoea index ≥1) and 22 were diagnosed to suffer from OSA. In general, sensitivity for both screening methods was low (<0.6), while specificity was moderately high (mostly >0.7). Independent predictors for OSA were body mass index, history of allergy, a composite questionnaire score, and two oximetry-based criteria. Based on these variables and logistic regression, a prediction model (accuracy; 95% confidence interval: 0.86; 0.71-0.94) was constructed and applied to children who had not successfully undergone polysomnography. This resulted in nine additional OSA cases and an overall design-adjusted population prevalence (95% confidence interval) of 2.8% (1.5-4.1%). Clinical and oximetry findings may be helpful for screening and predicting OSA in primary school children.

Vaccination coverage against measles in German-born and foreign-born children and identification of unvaccinated subgroups in Germany

Data from the representative German Health Interview and Examination Survey for Children and Adolescents were used to identify unvaccinated subgroups that should be targeted by vaccination programmes in order to interrupt measles transmission. Measles vaccination coverage was low among children below the age of 3, having > or =3 siblings and in foreign-born migrants. Multivariate analyses show that vaccination coverage was strongly related to the place of birth in migrants: foreign-born children have a three-fold odds of being unvaccinated. Odds were also higher in children living in former West Germany, having > or =3 siblings, and it was especially high in children with parents reporting reservations against vaccinations.

The German case-control scene investigation study on SIDS: epidemiological approach and main results

The present study, which was part of the German SIDS Study (GeSID), enrolled sudden infant death syndrome (SIDS) cases and population controls and obtained objective scene data via specifically trained observers shortly after discovery of each dead infant. Infants who had died suddenly and unexpectedly at ages between 8 and 365 days were enrolled in five regions of Germany between November 1998 and October 2001. Shortly after discovery of each dead infant, a specially trained doctor of legal medicine visited the bereaved family at home. Data were obtained by measurements and observations. Dead infants underwent a standardised autopsy, additional information being obtained by standardised parent interviews. Investigation of the sleep environment and wake-up scene in matched controls followed the same protocol. A total of 52 SIDS cases and 154 controls were enrolled, 58% were boys, and median age of cases vs. controls was 126 vs. 129 days. Risk factors in the sleeping environment were pillow use (adjusted OR 4.3; 95%CI 1.6-11.6), heavy duvets (OR 4.4; 1.5-13.3), soft underlay (OR 3.0; 1.1-8.7), face covered by bedding (OR 15.8; 2.5-102.1) and entire body covered by bedding (OR 35.5; 5.5-228.3). Using a standardised protocol, including objective measurements of the sleep environment and a case-control design, this study was able to confirm many risk factors for SIDS.

[Health care needs of children and adolescents with chronic conditions]

Using data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), we studied the association between chronic health conditions and specific health care needs among children and adolescents in Germany. A chronic health condition was defined based on standardized parent questionnaires and computer-assisted parent interviews regarding any lasting illness or health problem, congenital malformation or officially recognized disability. As part of the parent questionnaire, the validated German version of the Children with Special Health Care Needs (CSHCN) screener was used to assess special health care needs. Overall, 38.7% of the study population had at least one chronic health condition, as compared to 73.0% of children and adolescents who were identified as having specific health care needs. Only 25.8% of children and adolescents with chronic health conditions were found to have any special health care needs. However, this proportion varied considerably according to the type of health condition. Overall 3.7% of study participants screened positive for special health care needs, while no specific chronic health condition was reported by their parents. In multiple logistic regression analyses, factors independently associated with the absence of perceived health care needs among children and adolescents with chronic health conditions included female gender, migration background, a lower socioeconomic status, residence in former West Germany, a lower number of concomitant health problems, and the absence of behavioural problems. The identification of special health care needs among children and adolescents without any reported chronic health condition was determined by male gender, having no migration background, and evidence of behavioural problems. Further analyses are necessary to elucidate the relationship between chronic health conditions and health care needs among children and adolescents. These need to focus on specific health conditions and should include additional information on health-related quality of life, health care services use, and psychosocial resources.

The challenge of comprehensively mapping children's health in a nation-wide health survey: design of the German KiGGS-Study

Background

From May 2003 to May 2006, the Robert Koch Institute conducted the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). Aim of this first nationwide interview and examination survey was to collect comprehensive data on the health status of children and adolescents aged 0 to 17 years.

Methods/Design

Participants were enrolled in two steps: first, 167 study locations (sample points) were chosen; second, subjects were randomly selected from the official registers of local residents. The survey involved questionnaires filled in by parents and parallel questionnaires for children aged 11 years and older, physical examinations and tests, and a computer assisted personal interview performed by study physicians. A wide range of blood and urine testing was carried out at central laboratories. A total of 17 641 children and adolescents were surveyed – 8985 boys and 8656 girls. The proportion of sample neutral drop-outs was 5.3%. The response rate was 66.6%.

Discussion

The response rate showed little variation between age groups and sexes, but marked variation between resident aliens and Germans, between inhabitants of cities with a population of 100 000 or more and sample points with fewer inhabitants, as well as between the old West German states and the former East German states. By analysing the short non-responder questionnaires it was proven that the collected data give comprehensive and nationally representative evidence on the health status of children and adolescents aged 0 to 17 years.

[Use of medical services. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

The use of operations, visits to doctors and early diagnostic tests for children are examples of different services selected from the whole spectrum of preventative and therapeutic health service provisions in childhood and adolescence. In the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), which is representative for Germany, 17,641 children and adolescents aged 0-17 or their parents were questioned on subjects such as their use of medical services. The use made of individual early diagnostic tests for children remains above the 90 % limit until the U7 test and drops to 89.0 % at U8, falling to 86.4 % at U9. 81 % of children took part in all the early diagnostic tests provided until age 6 (U3 to U9). Another 16 % only took advantage of some parts of this service and 3 % of the children never went to one of these check-ups. As was to be expected, the annual rate of visits to paediatricians drops as children get older from 95.1 % for 0-2-year-olds to 25.4 % of the 14-17-year-olds, while the rate of visits to general practitioners rises from 11.8 % to 53.1 %. If one tracks the rate of visits to specialist doctors all the way across childhood and adolescence, different paths emerge: while children aged 3-6 most often visit the ear, nose and throat doctor, at primary school age they mainly see opticians, and 14-17-year-olds most often visit doctors of internal medicine, dermatologists and surgeons. 37.1 % of the 0-17-year-old children and adolescents had undergone an operation. In order of declining frequency, the operations named were adenoidectomy (15.2 %), tonsillectomy (5.9 %), herniotomy (3.6 %) and appendectomy (2.4 %). Circumcisions had been carried out on 10.9 % of the boys. The different way medical services are used in different subgroups may not only depend on medical factors but also on social factors, medical attitudes and the availability of services provided.

[Prevalence and characteristics of children and youth with special health care needs (CSHCN) in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

In order to arrive at population-based estimates on the prevalence and characteristics of children and adolescents with specific health care needs (CSHCN), screening instruments focussing on the consequences of physical, mental and behavioral problems rather than on medical diagnoses have been developed. One of the most feasible and widely tested instruments, the CSHCN screener was added to the self-administered questionnaire for parents of children participating in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). The overall weighted prevalence of CSHCN was 16.0% among boys and 11.4% among girls. Children at kindergarten or school age were more than 2-3 times more likely to screen positive compared to toddlers. Up to 14 years, the sex difference persisted through all age groups and was most pronounced between the ages of 3 and 10 years. Children with a migrant background had significantly lower rates of CSHCN compared to non-migrants. This was particularly true for boys (8.0% vs. 17.1%). CSHCN status was not related to social status, urbanization or residence in former West vs. former East Germany. Except for the lack of association with social status, these results are in good accordance with observations from the US National Survey of CSHCN.

[Prevalence of somatic diseases in German children and adolescents. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

In the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), which was conducted from 2003 to 2006, data on acute/infectious and chronic diseases were collected from a population-based sample of 17,641 subjects aged 0 to 17 years. The annual prevalence rates among acute diseases vary widely. Children and adolescents are most frequently affected by acute (infectious) respiratory conditions. 88.5 % of the surveyed children and adolescents experienced at least one episode of common cold within the last 12 months. Among the other acute respiratory infections, bronchitis and tonsillitis were the most frequently encountered conditions with 19.9 % and 18.5 %, respectively. The 12-month prevalence of otitis media and pseudocroup was 11 % and 6.6 %, respectively. 1.5 % of the children and adolescents experienced an episode of pneumonia. Apart from respiratory infections, gastrointestinal infections were very frequently stated as reasons for acute illness. Furthermore, 12.8 % of the children and adolescents experienced a herpetic infection, 7.8 % a conjunctivitis and 4.8 % a urinary tract infection. Lifetime prevalence rates of infectious diseases were as follows: pertussis 8.7 %, measles 7.4 %, mumps 4.0 %, rubella 8.5 %, varicella 70.6 %, scarlet fever 23.5 %. The various chronic somatic diseases in children and adolescents had different lifetime prevalence rates. Most frequently, children and adolescents were affected by obstructive bronchitis (13.3 %), neurodermatitis/atopic eczema (13.2 %) and hay fever (10.7 %). Scoliosis and asthma had been diagnosed by a doctor in 5.2 % and 4.7 % of subjects aged 0-17 years, respectively. The lifetime prevalence rates of the remaining diseases varied between 0.14 % for diabetes mellitus and 3.6 % for convulsions/epileptic fits. For the first time ever, these survey results provide nationwide representative information on the prevalence rates of acute/infectious and chronic diseases in children and adolescents which is based on a population-representative sample.

[Allergic diseases. Results from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

In the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) from 2003-2006 information was collected on allergic diseases (asthma, atopic dermatitis, hay fever, allergic contact eczema) from a population-based sample of 17,641 0-to 17-year-olds, and blood samples were studied for specific IgE antibodies to 20 common allergens. The lifetime prevalence (LTP) of at least one atopic disease was 22.9 % (95 % CI: 22.0-23.7 %), the 12-month prevalence (12MP) was 16.1 % (15.4-16.8 %); boys (17.3; 16.3-18.2 %) were more frequently affected than girls (14.9; 14.0-15.8 %). Children with a background of migration were less often currently affected by an atopic disease, as were children from families of low social status. According to parents' accounts, the LTP of allergic contact eczema was 9.9 % (9.4-10.5 %); girls (13.8;12.9-14.8) were more frequently affected than boys (6.2; 5.6-6.9 %). Of the 3- to 17-year-olds, 40.8 % (39.6-42.0 %) were sensitised to at least one of the allergens tested; boys (45.0; 43.5-46.5 %) more frequently so than girls (36.4; 35.0-37.9 %). In the states of the former FRG, the LTP of allergic contact eczema was higher (10.2; 9.6-10.9 %) than those in the former GDR (8.4 % 7.4-9.6 %); otherwise there were no East-West differences. The KiGGS data provide the first nationally representative data on allergic diseases and sensitisation. The differences in prevalence observed correspond to a great extent with previous studies and may support the hygiene hypothesis. The prevalences in East and West Germany now seem to have equalised.

Risk factors for sleep-related hypoxia in primary school children

Sleep-related hypoxia has adverse effects on cognition in children. Knowledge of factors contributing to sleep-related hypoxia is sparse. We aimed to identify demographic and clinical factors associated with mild (nadir arterial oxygen saturation 91-93%), moderate (nadir arterial oxygen saturation <or=90%), and recurrent (oxygen desaturation index > 3.9) sleep-related hypoxia in children. Parental questionnaires were distributed and overnight recordings of arterial oxygen saturation performed in a population-based cross-section of primary school children (n = 995). Associations were determined using unconditional logistic regression as well as unadjusted and adjusted odds ratios (OR), and their 95% confidence intervals (95% CI) calculated. Male sex, overweight (i.e., body mass index >or= 75th percentile), household smoking, symptoms of sleep-disordered breathing, a current respiratory tract infection, and histories of asthma and respiratory allergy were all significantly associated with sleep-related hypoxia. In multiple regression analysis, (i) overweight (OR, 95% CI: 2.7, 1.7-4.3) and a history of respiratory allergy (1.7, 1.1-2.7) were independent risk factors for mild sleep-related hypoxia, (ii) overweight (3.2, 1.7-5.8), a history of respiratory allergy (2.4, 1.4-4.4), and household smoking >10 cigarettes/day (1.8, 1.1-2.8) were independent risk factors for moderate sleep-related hypoxia, and (iii) overweight (2.3, 1.04-5.3), a history of respiratory allergy (2.5, 1.2-5.1), and a current respiratory tract infection (4.4, 2.0-9.8), were independent risk factors for recurrent sleep-related hypoxia. Our data suggest that overweight, passive smoking, respiratory allergies, and acute lung disease may independently contribute to sleep-related hypoxia in children.

Sleep problems and daytime somnolence in a German population-based sample of snoring school-aged children

Habitual snoring is associated with daytime symptoms like tiredness and behavioral problems. Its association with sleep problems is unclear. We aimed to assess associations between habitual snoring and sleep problems in primary school children. The design was a population-based cross-sectional study with a nested cohort study. The setting was twenty-seven primary schools in the city of Hannover, Germany. Habitual snoring and sleep problems were assessed in primary school children using an extended version of Gozal's sleep-disordered breathing questionnaire (n = 1144). Approximately 1 year later, parents of children reported to snore habitually (n = 114) and an equal number of children who snored never or occasionally were given the Sleep Disturbance Scale for Children, a validated questionnaire for the assessment of pediatric sleep problems. Snoring status was re-assessed using the initial questionnaire and children were then classified as long-term habitual snorers or ex-habitual snorers. An increasing prevalence of sleep problems was found with increasing snoring frequency for sleep-onset delay, night awakenings, and nightmares. Long-term habitual snorers were at significantly increased risk for sleep-wake transition disorders (e.g. rhythmic movements, hypnic jerks, sleeptalking, bruxism; odds ratio, 95% confidence interval: 12.0, 3.8-37.3), sleep hyperhidrosis (3.6, 1.2-10.8), disorders of arousal/nightmares (e.g. sleepwalking, sleep terrors, nightmares; 4.6, 1.3-15.6), and excessive somnolence (i.e. difficulty waking up, morning tiredness, daytime somnolence; 6.3, 2.2-17.8). Ex-habitual snorers were at increased risk for sleep-wake transition disorders (4.4, 1.4-14.2). Habitual snoring was associated with several sleep problems in our study. Long-term habitual snorers were more likely to have sleep problems than children who had stopped snoring spontaneously.

[Sexual maturation of children and adolescents in Germany. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

Following the standstill in maturity acceleration in the eighties of the twentieth century, now a further shift in maturity development towards younger ages is the issue of an international and also German discussion. The collection of sexual maturity data in boys and girls as part of the nationwide German Health Interview and Examination Survey for Children and Adolescents (KiGGS) is intended to pro vide population-representative information on sexual maturation and to evaluate associations between maturity status and selected health and social data. Girls were interviewed regarding their first menstrual period (menarche) and boys regarding voice change (status-quo method). Pubic hair was self-assessed by children and adolescents from 10 to 17 years of age, based on drawings of Tanner's defined developmental stages. The median age for menarche, for voice change and pubic hair stages were calculated using a logit model. At an age of 10 years, 42.4 % of girls and 35.7 % of boys report the development of pubic hair. At 17 years of age, the majority of girls and boys have reached the stages PH5 (girls 57.5 %, boys 47.8 %) and PH6 (girls 23.6 %, boys 46.5 %) according to Tanner. The average age for each pubic hair stage is lower in girls (PH2 10.8; PH3 11.7; PH4 12.3; PH5 13.4 years) than in boys (PH2 10.9; PH3 12.6; PH4 13.4; PH5 14.1). The median age at menarche is 12.8 years, the median for voice change (voice low) 15.1 years. Significant differences in age at menarche are found in girls depending on socioeconomic status (12.7/12.9/13.0 years for low/middle/high status) and between girls with and without migration background (12.5/12.9 years). No differences in age at menarche can be seen between East and West Germany or cities and rural areas. The association between maturity status and BMI is more pronounced in girls than in boys. Overall, the onset of maturity development in German children and adolescents is not significantly earlier than in other European studies.

Durchimpfung und Determinanten des Impfstatus in Deutschland

The level of childhood immunisation is an acknowledged indicator for health prevention. In Germany, vaccination is not compulsive. Continuous representative data derive only from school health examinations. From May 2003 until May 2006 the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) was conducted and vaccination information on 16,460 participants was obtained. Using data on the vaccination cards, it was possible to make detailed analyses of vaccination coverage in children up to the age of 17. Different vaccine types were taken into consideration in defining the term 'immunisation coverage'. The average prevalence of full immunisation for tetanus, diphtheria und polio as well as the coverage for the first dose of measles, mumps and rubella (MMR) vaccination was above 90% in children aged 2-17 years. Vaccination coverage for pertussis, Hib and hepatitis B is higher in younger than in older age groups. Compliance with the recommendation to have a second MMR dose and to make up of hepatitis B and pertussis immunisation is still low, especially in adolescents. In 7- to 17-year-old children the additional booster (recommended for 5- to 6-year-old children) is frequently missing.

Sudden infant death syndrome (SIDS)--standardised investigations and classification: recommendations

Sudden infant death syndrome (SIDS) still accounts for considerable numbers of unexpected infant deaths in many countries. While numerous theories have been advanced to explain these events, it is increasingly clear that this group of infant deaths results from the complex interaction of a variety of heritable and idiosyncratic endogenous factors interacting with exogenous factors. This has been elegantly summarised in the "three hit" or "triple risk" model. Contradictions and lack of consistencies in the literature have arisen from diverse autopsy approaches, variable applications of diagnostic criteria and inconsistent use of definitions. An approach to sudden infant death is outlined with discussion of appropriate tissue sampling, ancillary investigations and the use of controls in research projects. Standardisation of infant death investigations with the application of uniform definitions and protocols will ensure optimal investigation of individual cases and enable international comparisons of trends.

Reference values for nocturnal home polysomnography in primary schoolchildren

Abbreviated home polysomnography may be an alternative to laboratory polysomnography in children but is not yet generally accepted, partly due to a lack of reference values. Also, there are no normative data on respiratory events obtained using nasal prongs. We determined the prevalence and frequency of central, obstructive, and mixed apneas and hypopneas in a population-based sample of 50 children (mean age 10.1 years) using abbreviated home polysomnography and nasal prongs. We also determined the frequency of movements/arousals and body position changes. All children had central apneas. Obstructive apneas, mixed apneas, and hypopneas were found in 36%, 6%, and 14% of children, respectively. Average number of central, obstructive, and mixed apneas; hypopneas; movement/arousals; and body position changes per hour of sleep was 1.5, 0.1, 0.01, 0.02, 8.2, and 3.7, respectively. The corresponding cutoff values (mean plus 2 standard deviations or 95th centile) were 3.7, 0.7, 0.1, 0.2, 13.4, and 9.1, respectively. We did not find significant gender differences regarding any sleep variable under study. The presented reference values may help clinicians and researchers to improve the interpretation of abbreviated home polysomnography in school-age children.

Nocturnal arterial oxygen saturation and academic performance in a community sample of children

OBJECTIVE

Hypoxemia, often assessed via pulse oximetry, is associated with neurocognitive deficits in children. The best way to qualify hypoxemia, or which level of hypoxemia already affects cognition, is unknown.

METHODS

We assessed the association of pulse oximetry-derived variables that qualify hypoxemia with impaired academic performance in mathematics in a population-based cross-section of 995 primary school children who underwent overnight home recordings of motion-resistant new-generation pulse oximeter saturation (SpO2). Impaired academic performance in mathematics was based on the last school report and defined as grade 4 to 6 on a 6-point scale (ie, approximately the lowest quintile grades).

RESULTS

Of 10 variables under study, only the nadir of the SpO2 values was significantly associated with impaired performance. Categories of this variable representing mild (ie, 91%-93% SpO2; odds ratio: 1.65; 95% confidence interval: 1.06-2.56) and moderate hypoxemia (ie, < or =90% SpO2 ; odds ratio: 2.28; 95% confidence interval: 1.30-4.01) both were associated with impaired performance in mathematics.

CONCLUSIONS

We suggest using the nadir of the SpO2 values in an overnight study to qualify hypoxemia in future studies. This variable may predict neurocognitive deficits in school children. Mild hypoxemia, as yet widely considered benign, may already affect cognition in childhood. SpO2

Risk factors and natural history of habitual snoring

STUDY OBJECTIVE

It has been suggested that habitual snoring (HS) has adverse health outcomes in children. We aimed to identify risk factors for HS and determine its natural history in primary school children.

DESIGN

Cross-sectional, population-based cohort study.

SETTING

Twenty-seven primary schools located within the city limits of Hannover, Germany.

PARTICIPANTS

Third-grade primary school children.

MEASUREMENTS AND RESULTS

Snoring frequency and potential risk factors were investigated using parental questionnaires. Unadjusted and adjusted odds ratios (ORs) for HS and their 95% confidence intervals (CIs) were calculated. One year after the initial contact, snoring status was re-evaluated in habitual snorers. In total, 1,760 children were contacted, and 1,144 parents and their children (49% were girls) agreed to participate and returned a completed questionnaire. A body mass index >/= 90th percentile (OR, 3.5; 95% CI, 1.8 to 7.1), low maternal education (OR, 2.3; 95% CI, 1.1 to 4.7), regular daytime mouth breathing (OR, 7.4; 95% CI, 3.5 to 15.6), and a higher frequency of sore throats (OR, 17.6; 95% CI, 6.4 to 48.8) were independent risk factors for HS. Parental smoking and frequent infections were significantly but not independently associated with HS. The association of low maternal education and HS was higher in boys (OR, 4.4; 95% CI, 1.5 to 13.6; vs OR, 1.2; 95% CI, 0.4 to 3.6), while that of sore throats and HS was higher in girls (OR, 52.7; 95% CI, 6.0 to 460.2; vs OR, 13.3; 95% CI, 3.0 to 58.5). At follow-up, 39 of 80 eligible habitual snorers (48.8%) still snored regularly. Children who continued to snore differed significantly in maternal education, household smoking, snoring loudness, and prior ear, nose, throat surgery from those who had ceased to snore habitually.

CONCLUSIONS

Socioeconomic status, obesity, signs of nasal obstruction, and pharyngeal problems were independent risk factors for HS in these primary school children. The expression of HS varied considerably over time.

The German study on sleep-disordered breathing in primary school children: epidemiological approach, representativeness of study sample, and preliminary screening results

In order to study the prevalence of habitual snoring (HS), obstructive sleep apnoea (OSA), other aspects of sleep-disordered breathing (SDB), and their determinants, we enrolled a cross-section of children from the population of third graders attending regular primary schools in Hannover, Germany. The recruitment strategy followed a multistage, probability-clustered design. Selected schools were compared with eligible schools regarding the percentage of children with low socio-economic status (SES). The recruitment process was analysed and response proportions calculated. Study subjects were compared with their school enrolment cohort based on anonymous data provided by school authorities. Habitual snoring and OSA were investigated using parental questionnaires and all children underwent nocturnal home pulse oximetry. There was a good overall representativeness of sampled schools with regard to the percentage of children with low SES. In total, 1760 children were contacted and 1144 (65.0%) agreed to participate. The whole process of self-selection of study subjects was not differential by gender. Compared with their school enrolment cohort, study subjects had slightly higher educated parents. The prevalence of HS was estimated to be 10.1% [95% CI 8.3, 11.9%]; and 3.2% [2.2, 4.2%] and 3.9% [2.8, 4.2%] had an abnormally high OSA or SDB score respectively. Based on pulse oximetry, 2.4% [95% CI 1.5, 3.4%] had 3 D(90)and 3 D(C), 1.0% [0.4, 1.6%] had the DI(90) > 0.6, and 3.3% [2.2, 4.4%] had the DI(4) > 3.9 and the DI(C) > 0.4. This study sample appears to be highly representative with regard to all available data from the population, and therefore suitable to study the prevalence of HS and OSA. Our prevalence estimates are in the range of other studies.

Habitual snoring, intermittent hypoxia, and impaired behavior in primary school children

OBJECTIVES

Sleep-disordered breathing is associated with impaired behavior and poor academic performance in children. We aimed to determine the extent of behavioral problems in snoring children, clarify the role of intermittent hypoxia, and test the reversibility of impaired behavior and poor academic performance.

METHODS

In 1144 children, habitual snoring (HS; snoring frequently or always) and impaired behavior were assessed using parental questionnaires. Intermittent hypoxia (ie, presence of > or =5 arterial oxygen desaturations by > or =4% or > or =1 desaturation to < or =90%) was investigated with pulse oximetry. Poor academic performance (grade 4-6 on a 6-point scale in mathematics, science, or spelling) was based on the last school report. HS, impaired behavior, and academic performance were reevaluated after 1 year. Adjusted odds ratios (ORs) were calculated using unconditional logistic regression.

RESULTS

HS was significantly associated with hyperactive (OR: 2.4) and inattentive behavior (OR: 4.0), daytime tiredness (OR: 7.1), and sleepiness (OR: 2.6-4.8). These associations were independent of intermittent hypoxia. HS was also significantly associated with bad conduct (OR: 2.8), emotional symptoms (OR: 5.5), and peer problems (OR: 9.7). At follow-up, hyperactive and inattentive behavior but not academic success had significantly improved in children in whom HS had ceased.

CONCLUSIONS

We suggest that impaired behavior is a key feature of HS independent of intermittent hypoxia and improves when HS ceases.

Inter- and intraobserver agreement for gastroesophageal reflux detection in infants using multiple intraluminal impedance

The multiple intraluminal impedance (MII) technique is a new method that allows pH-independent gastroesophageal reflux detection via changes in impedance caused by a liquid bolus inside the esophagus. We wanted to know whether this technique yields objective and reproducible results. Twenty 3- to 6-hour recordings of MII from 19 preterm infants (median gestational age at birth 30 weeks, range 24-34 weeks; age at study 26 days, range 13-93 days) were divided into 23-second segments and analyzed for reflux episodes by three investigators; one investigator analyzed the data set twice. Observer agreement was assessed using kappa statistics. Each investigator analyzed 16,627 23-second segments, with a median of 854 (range 486-979) segments per recording. Median kappa values for the 20 recordings were 0.79, 0.83, and 0.83 for the three pairs of investigators and 0.84 for the repeated scoring procedure. MII recordings could be analyzed with a high level of inter- and intraobserver agreement.

Snoring, intermittent hypoxia and academic performance in primary school children

Sleep-disordered breathing is associated with impaired attention and neurocognitive deficits. We assessed the association of snoring and intermittent hypoxia with poor academic performance in third grade school children (1,144 children). Snoring frequency and intermittent hypoxia were investigated using parental questionnaire and nocturnal home pulse oximetry. Intermittent hypoxia was specified as desaturation events of 90% or less pulse oximeter saturation. Poor academic performance was defined as grade 4-6 on a six-point scale (i.e., approximately the lowest quintile grades) in mathematics, science, reading, spelling, and/or handwriting in the most recent school report. Snoring "always" was significantly associated with poor academic performance in mathematics (odds ratio; 95% confidence interval: 3.6; 1.3-10.1), science (4.3; 1.3-14.6), and spelling (3.5; 1.2-10.3). Snoring "frequently" was also significantly associated with poor academic performance in mathematics (2.4; 1.3-4.7) and spelling (2.0; 1.04-3.8). A significant relationship between snoring and poor academic performance was also found in children without intermittent hypoxia, whereas intermittent hypoxia did not show an independent association with poor academic performance. Thus, habitual snoring (i.e., snoring frequently or always) was associated with poor academic performance in these primary school children.

[Socioepidemic analysis of sources of information and medical care for a subpopulation of female and male participants in a nationwide informative campaign in Germany on "Danger Signal: Heartburn"]

Whilst the prevalence of gastroesophageal reflux is increasing, most people are unaware of its possible consequences. Therefore, in Autumn 2000 a nationwide information campaign was launched on the symptoms of gastroesophageal reflux and its possible treatments. One part of the information campaign was a telephone hotline which was followed by an interview by phone or a mailed questionnaire. The objective of this was to find out more about the people concerned and their complaints. The subjects of both data sets were on average 53 respectively 57 years old, half of them were female and over 60 % had had heartburn for more than two years. The interview showed that 53 % took notice of the hotline by a press release. The interviewed persons gathered information in general about health-related issues primarily from newspapers and TV reports and from their physician. 81.7 % of the questionnaire sample had already at least one gastroscopy. Another 9.5 % made use of medical services because of their complaints in the last year. 8.8 % used exclusively over-the-counter medication for relief from their complaints. These three groups of different degrees of utilisation differed in respect of age, intensity and duration of the symptom heartburn and lifestyle-factors such as smoking. Those who had a gastroscopy were older, symptoms were more prolonged, more severe, more often and comprised a wider range of symptoms and less cigarette consumption. The analysis of both samples showed that the telephone hotline was used mainly by people who had had their symptoms for a long time and had already been in medical care. The chosen means of information stated by the sample indicate that media are prominently involved in disseminating information and educating the public.

Reference values for nocturnal home pulse oximetry during sleep in primary school children

OBJECTIVE

To provide reference values for pulse oximeter saturation (SpO(2)) in primary school children, measured at home during sleep.

METHODS

Recordings of SpO(2) and signal quality from 100 children were randomly selected from a larger population-based sample intended to study the prevalence of sleep-disordered breathing. Recordings were analyzed for the duration of artifact-free recording time (AFRT), minimum SpO(2) (SATmin) and median SpO(2) (SAT(50)), the SpO(2) below which the child spent 5% of AFRT (SAT(5)), and the SpO(2) below which the child spent 10% of AFRT (SAT(10)). In addition, the time in seconds with SpO(2) <or= 90% per hour of AFRT (TI(90)) was calculated, as were the number of falls in SpO(2) by >or= 4% per hour of AFRT (DI(4)), the number of falls in SpO(2) to <or= 90% per hour of AFRT (DI(90)), and the number of falls in SpO(2) to <or= 92% per hour of AFRT (DI(92)).

RESULTS

Ten recordings had to be excluded because of insufficient AFRT (< 5 h). Mean age of the remaining 90 children (54 girls) was 9.3 years (SD, 0.6). Median (range; fifth centile) values for SATmin, SAT(5), SAT(10), and SAT(50) were 93% (76 to 97; 87.5), 97% (88 to 99; 95), 97% (89 to 99; 96), and 98% (94 to 100; 97). Median values (range; 95th centile) for TI(90), DI(4), DI(90), and DI(92) were 0.0 s (0.0 to 5.8; 1.6), 0.8 (0.0 to 6.1; 3.9), 0.0 (0.0 to 1.2; 0.2), and 0.0 (0.0 to 2.0; 0.6).

CONCLUSION

Baseline SpO(2) values < 97% were uncommon in these children, as were intermittent desaturations to <or= 90%. These data may serve as a basis for the interpretation of clinical recordings of SpO(2) in children referred for sleep-related breathing disorders.