The Danish National Birth Cohort--its background, structure and aim

BACKGROUND

It is well known that the time from conception to early childhood has importance for health conditions that reach into later stages of life. Recent research supports this view, and diseases such as cardiovascular morbidity, cancer, mental illnesses, asthma, and allergy may all have component causes that act early in life. Exposures in this period, which influence fetal growth, cell divisions, and organ functioning, may have long-lasting impact on health and disease susceptibility.

METHODS

To investigate these issues the Danish National Birth Cohort (Better health for mother and child) was established. A large cohort of pregnant women with long-term follow-up of the offspring was the obvious choice because many of the exposures of interest cannot be reconstructed with sufficient validity back in time. The study needs to be large, and it is aimed to recruit 100,000 women early in pregnancy, and to continue follow-up for decades. The Nordic countries are better suited for this kind of research than most other countries because of their population-based registers on diseases, demography and social conditions, linkable at the individual level by means of the unique ID-number given to all citizens. Exposure information is mainly collected by computer-assisted telephone interviews with the women twice during pregnancy and when their children are six and 18 months old. Participants are also asked to fill in a self-administered food frequency questionnaire in mid-pregnancy. Furthermore, a biological bank has been set up with blood taken from the mother twice during pregnancy and blood from the umbilical cord taken shortly after birth. Data collection started in 1996 and the project covered all regions in Denmark in 1999. By August 2000. a total of 60,000 pregnant women had been recruited to the study. It is expected that a large number of gene-environmental hypotheses need to be based on case-control analyses within a cohort like this.

Do pregnant women report use of dispensed medications?

Surveillance of drug safety in pregnancy often draws on administrative prescription registries. Noncompliance in the use of prescribed medication may be frequent among pregnant women owing to their fear of fetotoxic side effects. To estimate compliance in the use of prescription drugs dispensed during pregnancy, we compared prescription data from the North Jutland Prescription Database with information on drug use provided by pregnant women to the Danish National Birth Cohort (DNBC), which is a health interview survey. We used the North Jutland Prescription Database to identify all prescription drugs dispensed during pregnancy for the 2,041 women who were enrolled in the DNBC in the County of North Jutland, Denmark. Compliance was defined as the probability of reporting drug use in DNBC after purchasing a dispensed prescription drug. The overall compliance to drugs purchased within 120 days before the interview was 43% (95% confidence interval = 40-46). Drugs used for treating chronic diseases, for example, beta-blockers, insulin, thyroid hormones, and diuretic and antiepileptic drugs, were always reported to be used, but compliance was low for drugs used for local or short-term treatment such as antihistamines, antibiotics, antacids, nonsteroid anti-inflammatory drugs, and gynecologic drugs. Thus, for the latter drug groups the prescription database may provide an incomplete identification of exposure. Neither data source is unbiased regarding actual drug intake. Nevertheless, our results indicate that for some drug groups risk assessment studies based on prescription data may produce false negative results as a result of noncompliance.

Smoking during pregnancy and infantile colic

OBJECTIVE

To evaluate the association between maternal smoking during pregnancy and infantile colic (IC).

METHODS

A follow-up study of singleton infants delivered by Danish mothers at the Aarhus University Hospital from May 1991 to February 1992 and still living in the municipality of Aarhus at the age of 8 months was conducted. A total of 1820 mothers and their infants were included. Self-administered questionnaires were used to collect data on smoking, other lifestyle factors, and sociodemographic variables at 16 and 30 weeks of gestation and 8 months postpartum. IC was defined in the 8-month questionnaire and based on Wessel's criteria, except that we used only the crying criterion.

RESULTS

IC was seen in 10.8% of all infants. We observed a twofold increased risk of IC among infants whose mothers smoked 15 or more cigarettes per day during their pregnancy(relative risk: 2.1; 95% confidence interval: 1.4-3.2) or in the postpartum period (relative risk: 2.0; 95% confidence interval: 1.3-3.1). Women who smoked continuously during pregnancy and the postpartum period had a relative risk of 1.5 (95% confidence interval: 1.1-2.0) of having a infant with IC compared with women who did not smoke during this period. Adjustment for maternal age, parity, marital status, alcohol intake, birth weight, gestational age, breastfeeding, caffeine intake postpartum, and paternal smoking did not change the effect measures.

CONCLUSION

The results indicate that maternal smoking during pregnancy may increase the risk of IC.

Immersion autometallographic tracing of zinc ions in Alzheimer beta-amyloid plaques

An easy to perform autometallographic technique (AMG) for capturing zinc ions in Alzheimer plaques is presented. The possibility of visualizing loosely bound or free zinc ions in tissue by immersion autometallography (iZnS(AMG)) is a relatively recent development. The iZnS(AMG) staining is caused by zinc-sulphur nanocrystals created in 1-2 mm thick brain slices that are immersed in a 0.1% sodium sulphide, 3% glutaraldehyde phosphate buffered solution, the NeoTimm Solution (NTS), for 3 days. When the zinc-sulphur nanocrystals are subsequently silver-enhanced by autometallography, the plaques are readily identified as spheres of dark interlacing strands of different sizes, embedded in the pattern of zinc-enriched terminals. The zinc specificity of the iZnS(AMG) technique was tested by immersion of brain slides in the chelator DEDTC prior to the NTS immersion. The iZnS(AMG) detection of zinc ions is easily standardized and can be used in the quantification of plaques with stereological methods. This technique is the first to detect zinc in plaques in the cerebellum of transgenic PS1/APP mice and the first to detect zinc ions in plaques and dystrophic neurites at electron microscopical levels.

Fetal growth and infantile colic

AIM

To describe how fetal growth and gestational age affect infantile colic, while considering other potential risk factors.

STUDY DESIGN

A population based follow up study of 2035 healthy singleton infants without any disability born to Danish mothers. Information was collected by self administered questionnaires at 16 and 30 weeks of gestation, at delivery, and 8 months post partum. Infantile colic is defined according to Wessel's criteria, but symptoms are restricted to crying for more than three hours a day, for more than three days a week, and for more than three weeks.

RESULTS

The cumulated incidence of infantile colic was 10.9%. Low birth weight babies (< 2500 g) had more than twice the risk (odds ratio = 2.7, 95% confidence interval 1.2 to 6.1) of infantile colic when controlled for gestational age, maternal height, and smoking.

CONCLUSION

Low birth weight may be associated with infantile colic, and further research will be aimed to focus on fetal growth and infantile colic.

Socioeconomic factors and risk of hospitalization with infectious diseases in 0- to 2-year-old Danish children

Although the association between low socioeconomic status and illness in childhood is well known, the impact of socioeconomic factors on risk and frequency of hospitalizations for infectious diseases, the most frequent disease category, during the first 2 years of life has scarcely been studied. Through linkage of records drawn from public administrative and health registries, we conducted a population-based cohort study of 5024 Danish children born in 1997 to examine the frequency of hospitalization for infectious diseases in very young children. The main exposure variables, adjusted for potential confounding factors, were mother's education level, household income, and cohabitation status. The outcome was number of hospital admissions (0, 1-2, or 3+) for infectious diseases. A total of 737 children (14.7%) were admitted to hospital 1-2 times, and 83 (1.6%) were admitted 3-10 times. The risk of hospitalization was increased in children of mothers with a low level of education compared with vocational education (1-2 admissions: adjusted odds ratio (OR) 1.3 (95% confidence interval [CI]: 1.1-1.6). Children from low-income families had an increased risk of 3 or more admissions (low cf middle income: adjusted OR 2.0 [95% CI: 0.6-6.0]). Children of single mothers had an increased risk of hospitalization (1-2 admissions: adjusted OR 1.7 [95% CI: 1.1-2.6]. We found the highest risk of hospitalization for infectious diseases in children of mothers with only basic schooling, and particularly among those coming from single parent homes with a low income.

Gestational age, small for gestational age, and infantile colic

BACKGROUND

Preterm and growth restricted infants may have developmental delays and deviations from normal organ function related to the gastrointestinal tract and the central nervous system. Since both organ systems are hypothesised to be involved in the pathogenesis of infantile colic, a condition characterised by excessive crying during the first months of life, impaired fetal growth and preterm birth may be risk factors for infantile colic.

METHODS

A total of 62,761 liveborn singletons from the Danish National Birth Cohort (1996 to 2002) were studied. Infantile colic was defined according to Wessel's modified criteria based on maternal interview conducted at 6 months post-partum.

RESULTS

A total of 2605 (4.2%) infants were born preterm, 54,441 (86.7%) at term, and 5715 (9.1%) post-term. A total of 4964 (7.9%) infants fulfilled Wessel's modified criteria for infantile colic. The risk for infantile colic increased with decreasing gestational age after adjustment for covariates. The highest odds [odds ratio (95% confidence interval)] was observed for infants born before 32 completed gestational weeks (1.5 [95% CI 1.0, 2.2], reference: 40 gestational weeks). Small for gestational age infants (birthweight below 10th percentile) had an increased odds of infantile colic (1.2 [95% CI 1.1, 1.3]) in all gestational age groups.

CONCLUSIONS

We observed an increased risk of infantile colic in preterm and small for gestational age infants in a large cohort. Our results suggest that the aetiology of infantile colic may be found in the prenatal, perinatal, and neonatal period.

Influence of day care attendance on the use of systemic antibiotics in 0- to 2-year-old children

OBJECTIVE

To examine the association between time spent in different public day care settings and prescription of systemic antibiotics. Design. Population-based cohort study of 5035 Danish children born in 1997 followed from birth to June 30, 1999.

METHODS

The study was performed by the linkage of records drawn from administrative registries. Exposure was the total time spent in a day care home or day care center. Outcome was the first prescription of a systemic antibiotic. Possible perinatal and sociodemographic confounding factors were considered by statistical analysis.

RESULTS

During the first year of life, 39.8% of the girls and 51.1% of the boys received at least 1 antibiotic prescription drug. Enrollment in a day care setting doubled a child's risk of receiving a prescription drug (adjusted relative risk in day care home 1.9, 95% confidence interval: 1.7-2.0; adjusted relative risk in day care center 2.0, 95% confidence interval: 1.7-2.3). Only age confounded the analyses. Age >1 year at the starting time in day care reduced the risk of receiving antibiotic prescriptions during the first 3 months after enrollment.

CONCLUSIONS

Enrollment in public day care facilities raised the risk of receiving an antibiotic prescription drug to the same extent in day care homes as well as in day care centers, so we cannot recommend one facility over the other based on the present study. Children <1 year old at enrollment were most at risk, suggesting that extension of parental leave may reduce the use of antibiotics.

The Soma Assessment Interview: new parent interview on functional somatic symptoms in children

OBJECTIVE

Medically unexplained or functional somatic symptoms (FSS) in children constitute a major clinical problem. Epidemiological studies of this phenomenon are, however, hampered by a lack of good standardized measures. The objective of this study was therefore to (1) develop a parent-report measure of FSS in children aged 5-10 years and (2) perform an initial validation.

METHODS

A parent interview, the Soma Assessment Interview (SAI), for FSS detection in young children was developed for lay interviewers with subsequent clinical assessment. A preliminary validation was based on interview tests of the parents of 54 children with well-defined physical disease, 59 with likely functional disorder and 105 from the community. Independent measures of the somatic complaints were completed before the interview, and children from the clinical samples were also assigned independent FSS diagnoses based on medical record review.

RESULTS

The Kappa value for two clinical assessors' agreement on FSS recognition was 0.86. Good discrimination was obtained between a community sample and a clinical sample with an expected high prevalence of FSS. In the former convergent validity with independent measures of somatic complaints was found. In the latter substantial agreement (89%) appeared between a medical record diagnosis of FSS and SAI detection of FSS.

CONCLUSION

The SAI offers comprehensive description of FSS in young children in population-based studies and may also prove useful in clinical settings. It is readily accepted and relatively quickly completed, and preliminary assessment of its validity is promising.

Nicotine replacement therapy during pregnancy and infantile colic in the offspring

OBJECTIVE

To investigate the associations between use of nicotine replacement therapy (NRT) and smoking during pregnancy and infantile colic in the offspring.

METHODS

We used data from maternal interviews (from pregnancy and at 6 months post partum) from the Danish National Birth Cohort (1996-2002). We included 63 128 live-born singletons with complete information on nicotine exposure during pregnancy and infantile colic symptoms as recorded at 6 months of age.

RESULTS

A total of 46 660 infants (73.9%) were unexposed to nicotine during pregnancy; 207 (0.3%) were exposed to NRT, 15 016 (23.8%) were exposed to smoking, and 1245 (2.0%) to both. A total of 4974 (7.9%) infants fulfilled Wessel's modified criteria for infantile colic. Prenatal nicotine exposure was associated with elevated risk for infantile colic in the offspring. Compared with the unexposed, NRT users had an adjusted odds ratio (OR) (95% confidence interval) of 1.6 (1.0-2.5; P = .03), smokers had OR = 1.3 (1.2-1.4), and women who both smoked and used NRT had OR = 1.6 (1.3-1.9). Partners' smoking was not associated with infantile colic after adjustment for maternal smoking.

CONCLUSIONS

We corroborated the association between smoking and infantile colic after adjustment for several possible confounders in a large cohort study. Moreover, we found that infants exposed to NRT prenatally had an increased risk for infantile colic of the same magnitude as those exposed to tobacco smoke. Thus, nicotine may play a role in the pathogenesis of infantile colic.

Psychosocial distress during pregnancy and the risk of infantile colic: a follow-up study

AIM

To examine the association between psychosocial exposures during pregnancy and the risk of infantile colic.

METHODS

The study included 378 infants and was conducted as a substudy of the Danish National Birth Cohort from 1997 to 1999, with prenatal data collected twice during pregnancy. A diary with a record for postpartum weeks 4-8 was used to quantify the amount of the infants' crying and fussing.

RESULTS

The cumulative incidence proportion of infantile colic was 8.2%. A threefold increased risk of infantile colic (OR = 3.7; 95% CI: 1.1-13.2) was found for mothers who reported distress during pregnancy. Close to a twofold increased risk of IC was found for the women who scored higher than 8 on the psychological distress scale (adjusted OR = 1.9; 95% CI: 0.5-7.2).

CONCLUSION

The results indicate that general distress during pregnancy influences the risk of infantile colic. Whether or not this relationship is causal requires further investigations.

Developmental Coordination Disorder in Children with a History of Infantile Colic

OBJECTIVE

To investigate whether children with a history of infantile colic showed impaired motor development at age 7 years compared with unaffected peers.

STUDY DESIGN

We studied 27,940 children from the Danish National Birth Cohort (1997-2002), including 1879 (6.8%) with a history of infantile colic. Infantile colic was defined according to the modified Wessel criteria as crying for more than 3 hours per day and more than 3 days per week. We compared the parental Developmental Coordination Disorder Questionnaire 2007 (DCDQ'07) scores in children with and without infantile colic after adjustment for intrauterine exposures, feeding type, parity, maternal age, socioeconomic status, Apgar score, gestational age, and birth weight.

RESULTS

Children with a history of infantile colic had an elevated risk of scoring above the predefined cutoff limit of possible or suspected developmental coordination disorder (OR, 1.3; 95% CI, 1.0-1.7; P = .034). The mean total DCDQ'07 score was -0.4 point (95% CI, -0.8 to 0) lower in children with a history of infantile colic. Moreover, they were at higher risk for a low total score (OR for a 10-point decrease, 1.1; 95% CI, 1.0-1.1; P = .006) and a low general coordination score (OR, 1.3; 95% CI, 1.1-1.5, P = .000) in the DCDQ'07. All associations appeared to be stronger among boys, but no statistically significant effect measure modification between infantile colic and sex was found.

CONCLUSION

We found no evidence of a strong association between infantile colic and developmental coordination disorder in this large Danish cohort.

Normal Levels of Plasma Free Carnitine and Acylcarnitines in Follow-Up Samples from a Presymptomatic Case of Carnitine Palmitoyl Transferase 1 (CPT1) Deficiency Detected Through Newborn Screening in Denmark

Carnitine palmitoyl transferase (CPT) 1 A deficiency is a rare disorder of hepatic long-chain fatty acid oxidation. CPT1 deficiency is included in newborn screening programs in a number of countries to allow presymptomatic detection and early treatment of affected patients.We present a case of presymptomatic CPT1A deficiency detected through newborn screening in Denmark with diagnostic levels of carnitine and acylcarnitines in the initial dried blood spot. Levels of plasma-free carnitine and acylcarnitines in follow-up samples were normal, but reverted to diagnostic levels when the patient developed clinical symptoms at the age of 8 months. At that time, a diagnosis of CPT1A deficiency was confirmed by sequence analysis of the CPT1A gene revealing homozygosity for a novel c.167C>T variation in exon 3. Enzyme activity measurements showed a relatively mild enzyme defect with a decreased residual enzyme activity of 17-25%. We conclude that CPT1A gene testing and/or enzyme assay is mandatory to confirm an abnormal newborn screen suggesting CPT1A deficiency to avoid delayed diagnoses.

Zoledronate Increases Bone Mineral Density in Nonambulant Children With Cerebral Palsy: A Randomized Controlled Trial

CONTEXT

Zoledronate appears to reduce fracture rates in children with cerebral palsy (CP), but no previous randomized, controlled trial has been performed to compare the effect of zoledronate to placebo in children with CP.

OBJECTIVE

To investigate the effect of zoledronate on bone mineral density (BMD) Z-scores in children with nonambulant CP in a randomized, controlled, double-blind trial.

METHODS

Nonambulant children with CP (5 to 16 years of age) were randomized 1:1 to receive 2 doses of zoledronate or placebo at a 6-month interval. BMD Z-score changes at the lumbar spine and the lateral distal femur (LDF) were calculated from dual-energy x-ray absorptiometry scans. Monitoring included weight, bone age, pubertal staging, knee-heel length, adverse events, biochemical markers, and questionnaires.

RESULTS

Twenty-four participants were randomized and all completed the study. Fourteen were assigned to zoledronate. The mean lumbar spine BMD Z-score increased 0.8 SD (95% CI: 0.4; 1.2) in the zoledronate group, which was significant when compared to 0.0 SD (95% CI: -0.3; 0.3) in the placebo group. Similarly, the LDF BMD Z-scores increased more in the zoledronate group. Severe acute phase symptoms affected 50% of the patients in the zoledronate group but were reported exclusively after the first dose. Growth parameters were similar in both groups.

CONCLUSION

Zoledronate for 12 months increased BMD Z-scores significantly without affecting growth, but first-dose side effects were common and considerable. Studies into lower first doses and long-term outcomes are needed.

A medical record review for functional somatic symptoms in children

OBJECTIVE

The objectives of this study were to develop and test a systematic medical record review for functional somatic symptoms (FSSs) in paediatric patients and to estimate the inter-rater reliability of paediatricians' recognition of FSSs and their associated impairments while using this method.

METHODS

We developed the Medical Record Review for Functional Somatic Symptoms in Children (MRFC) for retrospective medical record review. Described symptoms were categorised as probably, definitely, or not FSSs. FSS-associated impairment was also determined. Three paediatricians performed the MRFC on the medical records of 54 children with a diagnosed, well-defined physical disease and 59 with 'symptom' diagnoses. The inter-rater reliabilities of the recognition and associated impairment of FSSs were tested on 20 of these records.

RESULTS

The MRFC allowed identification of subgroups of children with multisymptomatic FSSs, long-term FSSs, and/or impairing FSSs. The FSS inter-rater reliability was good (combined kappa=0.69) but only fair as far as associated impairment was concerned (combined kappa=0.29).

CONCLUSIONS

In the hands of skilled paediatricians, the MRFC is a reliable method for identifying paediatric patients with diverse types of FSSs for clinical research. However, additional information is needed for reliable judgement of impairment. The method may also prove useful in clinical practice.

Center differences in diabetes treatment outcomes among children with type 1 diabetes: A nationwide study of 3866 Danish children

OBJECTIVE

Mean differences in HbA_1c across centers are well established, but less well understood. The aim was to assess whether differences in patient case-mix can explain the variation in mean HbA_1c between pediatric diabetes centers in Denmark. The association between HbA_1c , frequency of blood glucose monitoring (BGM), treatment modality, and center visits was investigated.

RESEARCH DESIGN AND METHODS

This longitudinal nationwide study included 3866 Danish children with type 1 diabetes from 2013 to 2017 (n = 12,708 child-year observations) from 16 different pediatric diabetes centers. Mean HbA_1c , proportion of children reaching HbA_1c treatment target (HbA_1c  ≤ 58 mmol/mol [7.5%]) were compared across centers using linear regression models. This was done with and without adjustment for socioeconomic characteristics (patient case-mix).

RESULTS

The mean difference in HbA_1c during follow-up was 11.6 mmol/mol (95% CI 7.9, 15.3) (1.1% [95% CI 0.7, 1.4]) when comparing the centers with the lowest versus highest mean HbA_1c . The difference was attenuated and remained significant after adjustment for the patient case-mix (difference: 10.5 mmol/mol [95% CI 6.8, 14.2] (1.0% [95% CI 0.6, 1.3])). Overall, 6.8% of the differences in mean HbA_1c across centers were explained by differences in the patient case-mix. Across centers, more frequent BGM was associated with lower HbA_1c . The proportion of insulin pump users and number of visits was not associated with HbA_1c .

CONCLUSION

In a setting of universal health care, large differences in HbA_1c across centers were found, and could not be explained by patient background, number of visits or use of technology. Only BGM was associated with center HbA_1c .

Suspicion of child maltreatment: Knowledge and experiences with mandatory reports to social services among general practitioners in Denmark in 2019-20

BACKGROUND

Child maltreatment has many consequences through the lifespan. The general practitioners (GPs) are in longitudinal contact with the family and can play an important role in identifying children in danger and reporting to the social services.

OBJECTIVE

To explore how GPs manage suspicions of child maltreatment and to investigate potential demographic and geographic differences in reporting practices among Danish GPs.

PARTICIPANTS AND SETTING

All registered GPs in Denmark retrieved from Medcom, a state-financed non-profit organization.

METHODS

We mailed a questionnaire to all registered GPs with demographics, experiences, knowledge, and attitudes in the context of child maltreatment.

RESULTS

We received 1252 completed questionnaires (response rate: 38 %). Most of the participants had suspected child maltreatment during their professional life (90 %) and had made a mandatory report (85 %). More than half had received feedback after the report (56 %) and said that their report led to action (56 %). Most GPs reported feeling confident in dealing with child maltreatment (79 %) and being willing to get involved in case of suspicion (8.9 on a 0-10 scale). We observed no geographical differences in reporting neither across the Danish regions nor among rural and urban practices, but GPs working in single practices made fewer reports to the social services.

CONCLUSIONS

Participant GPs in this study are aware of their role in child protection, have experiences with mandatory reports, and are willing to get involved. Possible areas for attention include collaboration and support between different settings, especially between GP practice, hospitals, justice sector, and social services.

Lethal abusive head trauma in infancy in Denmark from 2000 to 2011

INTRODUCTION

We aimed to estimate the incidence of lethal abusive head trauma (AHT) in infancy in Denmark from 2000 through 2011 and to describe autopsy findings and information from police reports on lethal AHT cases.

METHODS

This was a nationwide retrospective study. We identified AHT cases in the National Cause of Death Register (CODR) and in forensic archives and compared data from the two sources. Moreover, we collected data on medical history, witness statements and conviction reports from police files and the Director of Public Prosecutions.

RESULTS

We identified eight cases of lethal infant AHT (incidence: 1.04 per 100,000 person years). Three AHT cases from autopsy reports were not registered correctly in the CODR. The median age of the victims was 46.5 days. They all had recent subdural and/or subarachnoid haemorrhage. We also found a high prevalence of retinal haemorrhage and fractures. Seven perpetrators were identified, all male relatives, and all were convicted. We moreover identified a surprisingly large number of infants with unspecific cause of death and missing information on whether an autopsy had been performed in the CODR (n = 56).

CONCLUSIONS

The incidence of lethal infant AHT found in this study is lower than findings from most other countries. Data from the CODR are inadequate for identifying all lethal AHTs. Further studies including non-fatal cases of AHT are needed to determine the real incidence of AHT in Denmark.

FUNDING

none.

TRIAL REGISTRATION

not relevant.

[Mowat-Wilson syndrome: a report of three Danish cases]

Mowat-Wilson syndrome (MWS) is an autosomal dominant intellectual disability syndrome characterised by unique facial features and congenital anomalies such as Hirschsprung disease, congenital heart defects, corpus callosum agenesis and urinary tract anomalies. Some cases also present epilepsy, growth retardation and microcephaly. The syndrome is caused by mutations or deletions of the ZEB2 gene at chromosome 2q22-q23. MWS was first described in 1998 and until now approximately 180 cases have been reported worldwide. We report the first three molecularly confirmed Danish cases with MWS.

Cerebral palsy and bisphosphonates - and what can be learned from other types of secondary osteoporosis in children: A scoping review

AIM

We aimed to improve bone health management of children with cerebral palsy (CP) by reviewing studies investigating bisphosphonate therapy in children with CP and other types of secondary osteoporosis.

METHODS

We included trials on bisphosphonate treatment reporting any direct bone measurement or fracture outcome. All studies of patients with CP were included. We also included all controlled trials of children with secondary bone fragility as well as observational studies with ≥20 participants or at least 3 years of follow-up. Studies were assessed according to PRISMA guidelines using the RoB2-tool and the Newcastle-Ottawa Scale.

RESULTS

We reviewed 1104 studies and found 37 eligible. Some studies were sufficiently homogeneous to include in a meta-analysis, and we found a 1-year effect on lumbar spine bone mineral density (BMD) Z-score of +0.65 after oral and + 1.21 after intravenous bisphosphonates in children with secondary osteoporosis. Further, data on adverse events and post-treatment follow-up were reviewed. Limitations were heterogeneity and small size of the included studies.

CONCLUSION

Meta-analysis consistently showed significant BMD increases with bisphosphonates in children with secondary osteoporosis. Direct evidence of the effect of bisphosphonates on reducing fractures is lacking. We found no reports of long-term adverse events yet longer studies are needed.

[Infantile colic--an assessment of possible risk factors]

Infantile colic is defined as crying or fussing for more than three hours a day for more than three days a week. The aetiology is unknown, although many hypotheses have been examined: allergy, type of feeding, the development of the gastrointestinal tract, the development of the central nervous system, and the mother/infant relationship. The frequency varies between 8% and 40% in industrialised countries. We found that education, parity, age, obstetric factors, and gender were not important risk factors. There are no unambiguous results on psychosocial risk factors and infantile colic. Giving parents advice and education in parenting were more effective than changing diets. Elimination of cow's milk or the diet of the mother had some effect. This review comprises studies where infantile colic is defined quantitatively. Despite this, no unambiguous results, which are consistent with a multifactorial aetiology were found.