Comparing machine learning to a rule-based approach for predicting suicidal behavior among adolescents: Results from a longitudinal population-based survey.

INTRODUCTION: Suicidal thoughts and suicide attempts are one of the most prominent public health concerns in adolescents and therefore early detection is important to initiate preventive interventions and closer monitoring. METHOD: We examined whether the Machine Learning models Random Forest and Lasso Regression better predict future suicidal behavior than a simple decision rule that classifies every adolescent with history of suicide ideation at baseline as at risk (current practice). We used data from a general population of students in second and fourth year of secondary education in Amsterdam, the Netherlands. RESULTS: Both the Random Forest and the Lasso Regression resulted in slightly better prediction. The AUC of the Random Forest (0.79) and Lasso regression (0.76) were both higher than the AUC of the decision rule (0.64). The Random Forest achieved slightly (but non-significantly) higher sensitivity than the decision rule (0.37 versus 0.34), with the same specificity (0.94). With Lasso Regression the sensitivity increased significantly (0.52), but at the expense of the specificity (0.85). LIMITATIONS: The loss of cases after merging the data, the use of self-reported data, confidential data collection and the use of only four questions to measure suicidal behavior. CONCLUSIONS: This is the first study applying Machine Learning techniques to predict future suicidal behavior on survey data collected in a general population of adolescents. Our study showed that integrating machine learning techniques in screening practice will result in a small improvement in the ability to predict suicide. The models need to be further optimized to improve accuracy.

Psychometric properties of the Dutch-Flemish PROMIS® pediatric item banks Anxiety and Depressive Symptoms in a general population.

PURPOSE: This study aims to validate the Dutch-Flemish PROMIS pediatric item banks v2.0 Anxiety and Depressive Symptoms, the short forms 8a, and computerized adaptive tests (CATs) in a general Dutch population and to provide reference data. METHODS: Participants (N = 2,893, aged 8-18), recruited by two internet survey providers, completed both item banks. These item banks were assessed on unidimensionality, local independence, monotonicity, Graded Response Model (GRM) item fit, and differential item functioning (DIF) for gender, age group, region, ethnicity, and language. The short forms and CATs were assessed on reliability and construct validity compared to the Revised Child Anxiety and Depression Scale short version (RCADS-22) subscales. Reference scores were calculated. RESULTS: Both item banks showed sufficient unidimensionality, local independence, monotonicity, and GRM item fit, except for three Depressive Symptoms items that showed insufficient GRM item fit. No DIF was found when using ordinal regression analyses, except for two Depressive Symptoms items that showed DIF for language; all items showed DIF for language when using IRT PRO, except for one Anxiety item. Both short forms and CATs revealed sufficient reliability for moderate and severe levels of anxiety and depression, as well as high positive correlations with corresponding RCADS-22 subscales and slightly lower correlations with non-corresponding RCADS-22 subscales. CONCLUSION: The Dutch-Flemish PROMIS pediatric item banks v2.0 Anxiety and Depressive Symptoms, the short forms 8a and CATs are useful to assess and monitor anxiety and depression in a general population. Reference data are presented.

Contribution of overweight and obesity to the occurrence of adverse pregnancy outcomes in a multi-ethnic cohort: population attributive fractions for Amsterdam.

OBJECTIVE: To estimate the contribution of pre-pregnancy excessive weight to the occurrence of adverse pregnancy outcomes and to detect the differences in these contributions between different ethnic groups. DESIGN: Prospective multi-ethnic community-based cohort study. SETTING: The prevalence of excessive weight is increasing and in general higher in immigrant groups in many industrialised countries. Maternal excessive weight, like smoking during pregnancy, is an important risk factor for adverse pregnancy outcomes. POPULATION: A total of 8266 pregnant women, living in the Netherlands, were included in the ABCD study between January 2003 and March 2004. METHODS: After applying the exclusion criteria, the analysis included 7871 pregnancies. Binomial log-linear regression analyses were performed to estimate relative risks (RRs) expressing the association between overweight/obesity and small-for-gestational-age (SGA), large-for-gestational-age (LGA), preterm birth (PTB; <37 weeks of gestation) and extreme PTB (<32 weeks of gestation), controlling for parity, maternal age, education level and smoking. Next, the RRs were used to estimate population attributive fractions (PAF) for Amsterdam and separately for several ethnic groups. MAIN OUTCOME MEASURES: The RRs and PAFs. RESULTS: The PAFs for overweight/obesity were: SGA -4.9%, LGA 15.3%, PTB 6.6% and extreme PTB 22.0%. In absolute terms, this corresponds to -47 SGA infants, 126 LGA infants, 35 PTB and 20 extreme PTB per year in Amsterdam. Except for SGA, these PAFs were higher than those for smoking (6.2%, -3.9%, 5.5% and 10.6%, respectively). The contribution of overweight/obesity to LGA and PTB was higher in non-Western immigrant groups. CONCLUSIONS: Overweight/obesity has become an important contributor to the occurrence of adverse pregnancy outcomes in Amsterdam. For most outcomes, these contributions are larger than those for smoking. Development of special obesity prevention programmes for young women is required, especially focused on immigrant groups.

Relation of maternal hypertension with infant growth in a prospective birth cohort: the ABCD study.

The aim of this study was to investigate the assumed positive association of pre-existent and pregnancy-induced hypertension with the offspring's weight and length gain in the first 14 months of life. We studied 3994 pregnant women and their offspring in a prospective community-based cohort study, starting between 2003 and 2004 (Amsterdam Born Children and their Development, ABCD study). Questionnaires obtaining information about hypertension during pregnancy were completed, and this was complemented with additional information from the obstetric caregiver. Anthropometry of the offspring was followed during the first 14 months of life. Main outcome measures were presence or absence of growth acceleration in weight or length (normal: ΔSDS ⩽ 0.67 v. growth acceleration: ΔSDS > 0.67). The relation between hypertension during pregnancy and weight and length gain was addressed by logistic regression analyses. We found that pre-existent hypertension was related to growth acceleration in weight and length. After correction for birth weight and pregnancy duration, the effect remained significant for growth acceleration in weight (OR 1.89; 95% CI 1.21-2.97; P < 0.01). Pregnancy-induced hypertension showed similar results, although correction for birth weight and pregnancy duration rendered the associations non-significant. In conclusion, infants of women with pre-existent hypertension during pregnancy more frequently have growth acceleration in weight and length, and yet the mechanisms acting on postnatal growth appear to be different.

Promoting physical activity in children: The stepwise development of the primary school-based JUMP-in intervention applying the RE-AIM evaluation framework.

BACKGROUND: There is a lack of effective intervention strategies that promote physical activity (PA) in school children. Furthermore, there is a gap between PA intervention research and the delivery of programmes in practice. Evaluation studies seldom lead to adaptations in interventions that are subsequently evaluated by implementation on a wider scale. The stepwise development and study of JUMP-in aims to add knowledge to better understand how, when and for whom intervention effects (or lack of effects) occur. METHODS: This paper describes the stepwise development of JUMP-in, a Dutch school-based multi-level intervention programme, aimed at the promotion of PA behaviour in 6-12-year-old children. JUMP-in incorporates education, sports, care and policy components. JUMP-in consists of six programme components: 1. Pupil Follow-up Monitoring System; 2. School sports clubs; 3. In-class exercises with "The Class Moves!"; 4. Personal workbook "This is the way you move!"; 5. Parental Information Services; 6. Extra lessons in physical education, Motor Remedial Teaching and extra care. The process and effect outcomes of a pilot study were translated into an improved programme and intervention organisation, using the RE-AIM framework (Reach, Efficacy, Adoption, Implementation and Maintenance). This paper presents the process and results of the application of this framework, which resulted in a widescale implementation of JUMP-in. RESULTS: The application of the RE-AIM framework resulted in challenges and remedies for an improved JUMP-in intervention. The remedies required changes at three different levels: (1) the content of the programme components; (2) the organisation and programme management; and (3) the evaluation design. CONCLUSIONS: Considering factors that determine the impact of PA interventions in 'real life' is of great importance. The RE-AIM framework appeared to be a useful guide by which process and effect outcomes could be translated into an improved programme content and organisation.

The effect of neighbourhood income and deprivation on pregnancy outcomes in Amsterdam, The Netherlands.

BACKGROUND: Studies suggest that the neighbourhoods in which people live influence their health. The main objective of this study was to investigate the associations of neighbourhood-level income and unemployment/social security benefit on pregnancy outcomes: preterm delivery, small for gestational age (SGA), pregnancy-induced hypertension (PIH) and miscarriage/perinatal death in Amsterdam. METHODS: A random sample of 7883 from 82 neighbourhoods in Amsterdam. Individual-level data from the Amsterdam Born Children and their Development (ABCD) study were linked to data on neighbourhood-level factors. Multilevel logistic regression was used to estimate odds ratios and neighbourhood-level variance. RESULTS: After adjustment for individual-level factors, women living in low-income neighbourhoods (third, second and first quartiles) were more likely than women living in high-income neighbourhoods (fourth quartile) to have SGA births: OR 1.32 (95% CI 1.04 to 1.68), 1.42 (1.11 to 1.82) and 1.62 (1.25 to 2.08) respectively. Women living in the quartile of neighbourhoods with the highest unemployment/social security benefit were more likely than those living in the quartile with the lowest unemployment/social security benefit to have SGA births 1.36 (1.08 to 1.72). The neighbourhood-level variance was significant only for SGA births. No significant associations were found between neighbourhood-level factors and other pregnancy outcomes. CONCLUSION: The findings suggest that neighbourhood income and deprivation are related to SGA births. More research is needed to explore possible mechanisms underlying poor neighbourhood environment and pregnancy outcomes, in particular through stress mechanisms. Such information might be necessary to help improve maternal and fetal health.

Maternal pre-pregnancy body mass index explains infant's weight and BMI at 14 months: results from a multi-ethnic birth cohort study.

OBJECTIVE: To investigate the association between (self-reported) maternal pre-pregnancy body mass index (pBMI), and child's weight, height and BMI at age 14 months. DESIGN: Prospective multi-ethnic community-based cohort study. SETTING: Amsterdam, The Netherlands. PARTICIPANTS: 8266 pregnant women from the Amsterdam Born Children and their Development study, filled out a questionnaire covering socio-demographic data, obstetric history, lifestyle, dietary habits and psychosocial factors, 2 weeks after their first antenatal visit. 7730 gave birth to a viable term singleton infant with information on birth weight, gender and pregnancy duration. Growth data were available for 3171 of these children. MAIN OUTCOME MEASURES: Weight (g), height (cm) and BMI (kg/m(2)) of the child at age 14 months. RESULTS: pBMI was linearly associated with weight and BMI of the child at age 14 months. One unit increase in pBMI resulted in an increment of 29 g (95% CI 19 to 39) in weight and 0.041 kg/m(2) (95% CI 0.030 to 0.053) in BMI. The effect size decreased after adjustment for birth weight (weight: beta coefficient 19 g, 95% CI 10 to 28; BMI: beta coefficient 0.034 kg/m(2), 95% CI 0.023 to 0.046) and hardly changed after adjustment for all other variables (weight: beta coefficient 21 g, 95% CI 11 to 30; BMI: beta coefficient 0.031 kg/m(2), 95% CI 0.019 to 0.043). pBMI was not related to height. CONCLUSIONS: pBMI is an independent determinant of weight and BMI of the child at age 14 months. At least one third of this effect is mediated through birth weight.

Using health promotion outcomes in formative evaluation studies to predict success factors in interventions: an application to an intervention for promoting physical activity in Dutch children (JUMP-in)

JUMP-in is a systematically developed intervention aimed at promoting physical activity among primary school children. It is a joint project involving different authorities and entails six school-based programme components. Measuring effects of such an intervention is a complex challenge. A common problem is the lack of valid instruments to measure physical activity and its determinants. In addition, it usually takes years to find improvements in physical activity and related constructs like weight and fitness, or even in causal factors. For this reason different authors advocate for the establishment of 'health promotion outcomes'; (i) health literacy, (ii) social action and influence and (iii) healthy public policy and organizational practice. It is presumed that these health promotion outcomes lead to changes in determinants, behaviour and finally in health. Insight in these health promotion outcomes and information about input and through-put are important in discussing the impact and output. The formative evaluation study of the JUMP-in pilot shows the health promotion outcomes of the intervention. The health promotion outcomes 'social action and influence' and 'healthy public policy and organizational practices' were found to be positive. By measuring the presence of the conditions to achieve 'health literacy', it became clear that more attention must be paid to implementation in the future. Based on the health promotion outcomes, we expect that JUMP-in will be an effective intervention in the future. (AU)

Ethnic differences in preterm birth and its subtypes: the effect of a cumulative risk profile.

OBJECTIVE: To explore the effect of potentially explanatory risk factors on ethnic differences in the prevalence of preterm birth (PTB) and its subtypes. DESIGN: Prospective population-based cohort study. SETTING AND POPULATION: Pregnant women from Amsterdam attending their first antenatal visit for obstetric care. A total of 8266 women participated (response rate 67%). Ethnicity was based on the country of birth of the pregnant woman's mother: the Netherlands, Surinam, the Antilles, Turkey, Morocco, Ghana and other non-Dutch countries. Exclusion criteria were multiple births and gestational age at delivery less than 24 weeks. METHODS: Risk factors were obtained using a multilingual questionnaire and from the Dutch Perinatal Registration. Risk factors were summed into a cumulative risk score. Multiple logistic regression analyses were performed. MAIN OUTCOME MEASURES: Odds ratios with 95% CIs were calculated for total, spontaneous and iatrogenic (medically indicated) preterm births for the ethnic minority groups versus the Dutch reference group. RESULTS: After adjustment for all risk factors, the Surinamese (OR 1.6, 95% CI 1.2-2.4), Ghanaian (OR 2.0, 95% CI 1.1-3.6) and Antillean (OR 1.6, 95% CI 0.8-3.3) women had a higher risk of PTB compared with the Dutch women, in particular for iatrogenic preterm birth (OR 2.1, 95% CI 1.0-4.4; OR 3.2, 95% CI 1.0-10.4; OR 3.6, 95% CI 1.1-11.2, respectively). The ethnic minority groups had a higher cumulative risk score (ranging from 2.1 to 3.7) compared with the Dutch group (1.8). Adjustment for the cumulative risk score considerably decreased the risk of PTB among the Surinamese (OR 1.2, 95% CI 0.9-1.7), Ghanaian (OR 1.3, 95% CI 0.8-2.3) and Antillean (OR 1.2, 95% CI 0.6-2.4) women. CONCLUSIONS: A cumulation of risk factors, mainly observed among the ethnic minority groups, contributes to the explanation of ethnic differences in PTB prevalence.

Is psychosocial stress in first ongoing pregnancies associated with pre-eclampsia and gestational hypertension?

OBJECTIVE: Investigating the association of pre-eclampsia and gestational hypertension with psychosocial stress in the first half of pregnancy. DESIGN: Prospective community-based cohort study. SETTING: Amsterdam, The Netherlands. POPULATION: Between January 2003 and March 2004, all pregnant Amsterdam women (n = 12 377) were invited to fill in a questionnaire with sociodemographic and psychosocial variables (response rate 67%). Only nulliparous women with a singleton pregnancy, who completed the questionnaire before 24 weeks, and delivered after 24 weeks, were included. METHODS: A postpartum questionnaire was used to gather information on hypertension or proteinuria. If this questionnaire was not available, the national obstetric register was used for pregnancy outcome. Medical files were examined for women with hypertension and/or proteinuria to confirm the diagnosis of pre-eclampsia and gestational hypertension according to the International Society for the Study of Hypertension in Pregnancy guidelines. Psychosocial stress was defined as workstress (Work Experience and Appreciation Questionnaire partly based on the Job Content Instrument of Karasek et al.), anxiety (the State-Trait Anxiety Inventory), depression (Center for Epidemiological Studies Depression Scale) and pregnancy-related anxiety (PRAQ-R). The association of psychosocial stress with the incidence of pre-eclampsia and gestational hypertension was explored by multivariate analysis adjusted for sociodemographic and medical confounders. MAIN OUTCOME MEASURES: Incidence of pre-eclampsia and gestational hypertension. RESULTS: A total of 3679 women were included. The incidence of pre-eclampsia and gestational hypertension was 3.5 and 4.4%, respectively. Workstress, anxiety, pregnancy-related anxiety or depression had no effect on the incidence of pre-eclampsia or gestational hypertension. CONCLUSION: Psychosocial stress in the first half of pregnancy does not influence the incidence of pre-eclampsia and gestational hypertension in nulliparous women.

Late start of antenatal care among ethnic minorities in a large cohort of pregnant women.

OBJECTIVES: The objectives of this study were to investigate the difference in timing of the first antenatal visit between ethnic groups and to explore the contribution of several noneconomic risk factors. DESIGN: Prospective cohort study. SETTING: All independent midwifery practices in the city of Amsterdam and all six Amsterdam hospitals. POPULATION: Consecutive cohort of pregnant women (n = 12 381). Ethnic groups were distinguished by country of birth. METHODS: Questionnaire data showed possible risk factors for late start. A Cox-proportional hazards model was created with (1) only ethnic group and (2) the addition of all significant risk factors, both time fixed and time dependent. MAIN OUTCOME MEASURES: Gestational age at first visit. RESULTS: The questionnaire was returned by 8267 pregnant women (response rate 67%). All non-Dutch ethnic groups were significantly later in starting antenatal care during the whole duration of pregnancy compared with the ethnic Dutch group (hazard ratio [95% CI]: other Western, 0.83 [0.76-0.90]; Surinamese, 0.62 [0.56-0.68]; Antillean, 0.56 [0.45-0.70]; Turkish, 0.62 [0.55-0.69]; Moroccan, 0.56 [0.52-0.62]; Ghanaians, 0.50 [0.43-0.58] and other non-Western, 0.61 [0.56-0.67]). The range at which 90% were in care varied between 16 weeks and 3 days for Dutch and 24 weeks and 4 days for Ghanaians. These differences disappeared almost totally in the non-Dutch-speaking ethnic groups when the following risk factors were added to the model: poor language proficiency, low maternal education, teenage pregnancy, multiparity and unplanned pregnancy. The differences remained in the Dutch-speaking ethnic groups. CONCLUSIONS: We observed a disturbing delay by all ethnic groups in the timing of their first antenatal visit. In women born in non-Dutch-speaking, non-Western countries, these differences were explained by a higher prevalence of the risk factors: poor language proficiency in Dutch, lower maternal education and more teenage pregnancies. In women born in Dutch-speaking, non-Western countries, the disparities cannot be explained by higher prevalence of these risk factors, indicating that cultural factors play a role.

Ethnic differences in TSH but not in free T4 concentrations or TPO antibodies during pregnancy.

OBJECTIVE: To describe the TSH, free T4 and thyroid peroxidase antibody (TPO-Ab) concentrations during pregnancy among four ethnic groups and to determine reference values for these parameters during normal pregnancy. METHODS: Cross-sectional study of a cohort of 3270 pregnant women living in the city of Amsterdam. Blood samples were drawn at first booking in the first or second trimester. TSH, free T4 and TPO-Ab concentrations were determined. Four ethnic groups were studied: Dutch, Surinam, Turkish and Moroccan. RESULTS: Plasma TSH increased and free T4 decreased from the first to the second trimester of pregnancy for all the ethnic groups. Ethnic differences were observed in TSH concentrations, with Dutch females having the highest TSH levels compared to the other three ethnic groups. The median TSH difference was 0.16 mU/l between the Dutch and Moroccan women, 0.15 mU/l between the Dutch and Surinam women and 0.10 mU/l between the Dutch and Turkish women. These could not be explained by differences in age, parity and current smoking status. No differences were seen in free T4 concentrations between the four ethnic groups. The prevalence of TPO-Ab was comparable across the ethnic groups (about 6% in each); the concentration of TPO-Ab was also comparable among the ethnic groups. The Dutch women had a higher lower-limit (2.5 percentile) of the TSH reference range than the Surinam, Turkish and Moroccan women, ranging from 0.14 mU/l for the Surinam and Moroccan to 0.27 mU/l for the Dutch women. CONCLUSION: The increase in TSH and decrease in free T4 values during pregnancy correspond to previous reported studies. Pregnant Dutch women had consistently higher TSH values than the ethnic group, but corresponding free T4 levels and TPO-Ab did not differ between these ethnic groups.

Folic acid knowledge and use in a multi-ethnic pregnancy cohort: the role of language proficiency.

OBJECTIVE: To investigate the role of language proficiency as determinant of folic acid knowledge and use in a multi-ethnic pregnancy cohort. DESIGN: Prospective cohort study. SETTING AND POPULATION: Pregnant women from Amsterdam attending obstetric care for their first antenatal visit. Number approached: 12,373 women, response rate: 67% (8266 women aged 14-49 years). Ethnicity was based on the country of birth: the Netherlands, Surinam, Antilles, Turkey, Morocco, Ghana, other non-Western and other Western countries. MAIN OUTCOME MEASURES: Knowledge about and use of folic acid supplements in pregnancy as elicited in a multilingual questionnaire, as well as determinants of these in ethnic groups separately. RESULTS: Both periconceptional folic acid use and knowledge were significantly lower among Ghanaian, Moroccan, Turkish, and other non-Western women than among women born in the Netherlands or other Western countries. Language proficiency in Dutch was a major determinant of knowledge in all the ethnic groups with a mother tongue other than Dutch [adjusted odds ratios (OR): Western 3.2, non-Western (all countries combined) 7.5], while educational attainment was of secondary importance. Knowledge in turn was the strongest determinant of use (adjusted OR: Western 17.4, non-Western 27.0). CONCLUSIONS: Periconceptional folic acid supplement use among women born in non-Dutch-speaking non-Western countries is low, reflecting a lack of knowledge that is determined by the inability to speak and understand the language of the country of residence. Measures to tackle this problem include the provision of linguistically appropriate information via ethnic health advisors, and language courses integrating health education for immigrants.

Neck/shoulder, low back, and arm pain in relation to computer use, physical activity, stress, and depression among Dutch adolescents.

OBJECTIVE: To examine among adolescents (1) the prevalence of neck/shoulder, low back, and arm pain within different sociodemographic groups and (2) the association of neck/shoulder, low back, and arm pain with computer use, physical activity, depression, and stress. METHODS: A school-based questionnaire survey in 2002 and 2003 of neck/shoulder, low back, and arm pain, computer use, physical activity, depression, and stress. The survey was given to 3485 adolescents aged 12 to 16 years who attended secondary schools in Amsterdam, Netherlands. RESULTS: The overall prevalence of neck/shoulder, low back, and arm pain was 11.5%, 7.5%, and 3.9%, respectively. The prevalence of neck/shoulder pain was higher among girls and adolescents not living with both parents. The prevalence of low back pain also was higher among girls. Depressive symptoms were associated with neck/shoulder pain, low back pain, and arm pain. The stress experienced was associated with neck/shoulder pain and with low back pain. CONCLUSIONS: This study strengthens the findings that musculoskeletal pain is common among adolescents and is associated with depression and stress but not with computer use and physical activity.

The prevalence of encopresis in a multicultural population.

BACKGROUND: Population-based studies on the prevalence of encopresis in children are scarce and generally outdated. Prevalence estimates based on clinical studies are unreliable because parents tend to be reticent to seek medical help for this problem. Professional help is necessary, however, because encopresis can lead to serious psychosocial health problems. The authors examined the prevalence of encopresis in children, the frequency of visits made to general practitioners for encopresis and the psychosocial health problems of encopretic children. METHODS: This population-based study involved 13,111 parents and their 5- to 6-year-old children and 9,780 parents and their 11- to 12-year-old children, all residents of Amsterdam, the Netherlands. RESULTS: The prevalence of encopresis was 4.1% in the 5-to-6 age group and 1.6% in the 11-to-12 age group. Encopresis was more frequent among boys and children from the very depressed areas of the city. Encopresis was less frequent among Moroccan and Turkish children. A defecation frequency of less than three per week was found in 3.8% of the 5- to 6-year-olds and 10.1% of the 11- to 12-year-olds with encopresis. Only 37.7% of the 5- to 6-year-olds and 27.4% of the 11- to 12-year-olds who had encopresis had ever been taken to see a doctor for this problem. Psychosocial problems were far more common among children with encopresis than among normal children. CONCLUSIONS: Encopresis is a common condition that is often associated with psychosocial health disorders but only a small proportion of the children with encopresis are taken to a general practitioner to discuss their problem.

Vaccination rates in a multicultural population.

AIMS: To establish whether there are social or cultural groups of children in Amsterdam with relatively low vaccination coverage for diphtheria, pertussis, tetanus, and poliomyelitis (DPTP), and for measles, mumps, and rubella (MMR). METHODS: All of the 57,382 children aged between 5 and 12 years and living in Amsterdam on 1 January 2003 were analysed with respect to vaccination and sociodemographic data collected routinely by the Department of Child Health Care. The State Vaccination Programme (SVP) guidelines were adhered to in order to determine vaccination status. RESULTS: The overall respective DPTP and MMR vaccination rates were 93.0% and 93.9%. No great differences in vaccination levels were found between depressed and affluent areas or between the children of Dutch and non-Dutch mothers. However, foreign children who had been born abroad (Surinam, Morocco, Turkey) were most likely not to have been fully vaccinated. Children who attended anthroposophical schools were also found to be considerably less frequently fully immunised than those at other types of schools. CONCLUSIONS: Vaccination coverage for children domiciled in Amsterdam was very high. Nevertheless, there are groups where the vaccination level is relatively low and social contact is high.

[Prevalence of parental behaviour to diminish the crying of infants that may lead to abuse]. / Prevalentie van gedragingen van ouders om het huilen van zuigelingen te verminderen die kunnen leiden tot mishandeling.

OBJECTIVE: To estimate the prevalence of parental actions to stop infant crying that may threaten infant health, and to determine specific risk groups regarding these actions. DESIGN: Descriptive. METHOD: Before their visit to a well-baby clinic in the Netherlands, parents of 3345 infants aged 1-6 months (96.5% response) filled out an anonymous questionnaire on actions that they undertook to stop their child crying. RESULTS: At 6 months, 5.6% (95% confidence interval: 4.2-7.0%) of all the parents reported having smothered, slapped, or shaken their infant at least once because of its crying. The highest risks for detrimental parental actions were run by infants of parents from non-industrialised countries, of parents with no or only a part-time job, and of parents who had judged their infant's crying as excessive. CONCLUSION: Clinicians should be aware of the observed risk factors for abuse of young children known to cry a lot, in order to help parents to cope with this crying.

[Births and abortions among Amsterdam teenagers according to ethnicity, 1996-1998]. / Geboorten en abortussen bij Amsterdamse tienermeisjes naar etnische herkomst, 1996-1998.

OBJECTIVE: To determine the number of teenage births and abortions in Amsterdam, the Netherlands, in total and according to age and ethnic origin. DESIGN: Retrospective analysis of routinely collected data. METHOD: Based on data collected from the municipal population register and the abortion clinics in Amsterdam, birth rates, abortion rates and abortion ratios were calculated for the period 1996-1998. The birth rate was the number of live births and the abortion rate the number of abortions per 1000 teenage girls. The abortion ratio was the number of abortions per 100 pregnancies. RESULTS: The average birth rate and abortion rate for the period 1996-1998 were 3.2 and 7.6 for 14- to 16-year-old girls respectively, and 25.0 and 29.5 for 17- to 19-year-old girls respectively. Among 14- to 16-year-old girls 70 pregnancies out of 100 ended in an abortion and among 17- to 19-year-old girls 54 pregnancies out of 100. In both age groups the birth rate for Surinamese, Antillian, Moroccan, Turkish and Ghanian girls was higher than for Dutch girls. There was one exception: Moroccan girls aged 14-16 years did not have a higher birth rate than Dutch girls of the same age. Surinamese, Antillian and Ghanian girls aged 14-16 years and 17-19 years also had a higher abortion rate compared with Dutch girls of the same age. The Turkish and Moroccan girls did not have (much) higher abortion rates. In both age groups the abortion ratio was lowest for Turkish teenagers and highest for Ghanian teenagers. The figures for second-generation immigrant teenagers were more akin to those of the native Dutch girls than those of first-generation immigrants. CONCLUSION: In Amsterdam unwanted pregnancies were most frequent in Surinamese, Antillian and Ghanian teenage girls. To prevent these pregnancies further research into the (cultural) determinants of sexual behaviour is necessary.

[Increased percentages of breastfed infants in Amsterdam]. / Toegenomen percentages borstgevoede zuigelingen in Amsterdam.

OBJECTIVE: To investigate the prevalence of breastfeeding amongst infants in Amsterdam prior to and following an active breastfeeding policy that has been operating in Amsterdam since 1993; investigate the link between ethnic origin and breastfeeding and the reasons mothers give for stopping breastfeeding. DESIGN: Retrospective, descriptive study. METHOD: During the period 1998 to 2000, 1274 mothers in six child health centres in Amsterdam, the Netherlands, were asked about how they had fed their infant, aged 6 to 8 months, from the first week onwards, and their reasons for starting formula feeding. The breastfeeding percentages were compared with a study for the period 1992 to 1993. RESULTS: During the first week of the infant's life, 87% of the mothers gave breastfeeding, and at 25 weeks this figure was 30%. For the period 1998 to 2000, the breastfeeding rate at 15 weeks was higher compared with the period 1992 to 1993, 45.1% as opposed to 36.4%. An increased percentage of breastfed infants were found in each ethnic group studied. More Turkish and Moroccan mothers than Dutch mothers started to breastfeed, and they breastfed for a similar period. Surinam mothers started breastfeeding as often as Dutch mothers, but breastfed for a shorter period. Concern about inadequate milk supply was stated as the most important reason for starting formula feeding (44%). This was also the most important reason stated by each of the ethnic groups, Dutch (139/411; 34%), Surinam (63/129; 49%), Moroccan (70/130; 54%) and Turkish women (42/67; 63%). CONCLUSION: An active breastfeeding policy in Amsterdam that has been operating since 1993 has been accompanied by an increase in the number of breastfed infants. This has also been the case in non-Dutch groups. Health programmes should devote greater attention to mothers' concerns about a shortage of milk.

[High vaccination rates among children of Amsterdam]. / Hoge vaccinatiegraad van Amsterdamse kinderen.

OBJECTIVE: To examine if in Amsterdam there are social or cultural groups of children with a relatively low vaccination coverage for diphtheria, pertussis, tetanus and poliomyelitis (DPTP) and mumps, measles and rubella (MMR). DESIGN: Descriptive cross-sectional study. METHOD: In the Department of Child Health Care of the Municipal Health Service of Amsterdam all 83,217 children aged 2-12 years living in Amsterdam on the 1st of January 2000 were analysed for vaccination and sociodemographic data collected routinely by the Department of Child Health Care. The sociodemographic data concerned sex, year of birth, country of birth of the mother and child, name of the school and postal code of the home address. Schools were grouped by (religious) affiliation on the basis of the Amsterdam school guide 1999/2000. Based on postal codes children were classified by the neighbourhoods in which they were living. Neighbourhoods were grouped by socio-economic status based on data from the Central Bureau for Statistics. RESULTS: The overall vaccination rates of DPTP and MMR were 92.4% and 93.5% respectively. No important variation in vaccination coverage was identified between more and less affluent neighbourhoods. The uptake rate among foreign children was sometimes slightly higher and sometimes slightly lower compared with native children. Especially foreign children born abroad (Surinam, Antilles, Morocco, Turkey) were not fully vaccinated: 70.9% were fully immunized for DPTP, 79.5% for MMR. Children who visited anthroposophical schools were considerably less frequently fully immunized compared with children visiting other schools: for DPTP and MMR 81.0 and 59.9% respectively versus 94.4 en 95.3% for children attending general municipal schools. CONCLUSION: The vaccination coverage was high in children in Amsterdam. Further improvement of the vaccination uptake might be achieved by a more outreaching attitude to children born abroad, and by more intensely informing sceptical parents about the benefits and (supposed) dangers of vaccinations.