Etiological survey on intellectual disability in the northern Finland birth cohort 1986

The etiology of intellectual disability was studied both in incident (n = 9,432) and prevalent (n = 9,351) populations in a one-year birth cohort born in Northern Finland in 1985-1986. Data from multiple sources were used to follow the children until the age of 11.5 years. Of the incident cases (n=119) with intellectual disabilities, 66.4% had etiologically biomedical associative factor. Paranatal factors were relatively fewer and prenatal more common compared with earlier studies. We found nearly double the prevalence of genetic factors leading to intellectual disabilities compared with a contemporary study from Norway. The differences between the populations, despite random variation, some dissimilarities between etiological categorization and diagnostic accuracy, are in most part due to true differences between the study populations and genetic pool.     

The prevalence and nature of intellectual disability in Norwegian prisons

Background The objective of the study was to calculate the prevalence of inmates with intellectual disabilities (ID), and identify historical, medical and criminological characteristics of a certain impact. Methods A random sample of 143 inmates from a Norwegian prison cross sectional sample was studied. The Hayes Ability Screening Index (HASI) was validated with the Wechsler Abbreviated Scale of Intelligence (WASI). Results The prevalence of inmates with ID, IQ < 70, was 10.8%. Some essential characteristics of inmates with ID were more frequent medication for mental disorders, a higher number of imprisonments, less drug abuse and less education than the other inmates. The results indicated that the HASI is a valid tool for screening of ID for the Norwegian inmates. Conclusions The prevalence of ID in Norwegian inmates is significant, measured by WASI and HASI. Identification, rehabilitation and care, concerning an intellectual handicap, are mostly absent in the Norwegian criminal justice system.     

Children with intellectual disability in rural South Africa: prevalence and associated disability

Background The objective of the present study was to determine the prevalence of intellectual disability (ID) and its associated disabilities in rural South African children aged 2–9 years. It was undertaken in eight villages in the district of Bushbuckridge, Northern Province, South Africa. Methods A two‐phase design was utilized. The first phase involved screening children on a house‐to‐house basis by interviewing mothers or caregivers using an internationally validated questionnaire for detecting childhood disability in developing countries. The second phase consisted of a paediatric/neurodevelopmental assessment of the children who screened positive. Results A total of 6692 children were screened; 722 (10.8%) had a paediatric evaluation and 238 children were diagnosed with ID, giving a minimum observed prevalence of 35.6 per 1000 children in this population. The prevalence of severe and mild ID was 0.64 per 1000 and 29.1 per 1000 children, respectively. The male:female ratio of children with ID was 3:2. In the affected children, a congenital aetiology for the ID was determined in 49 subjects (20.6%), an acquired aetiology in 15 (6.3%) and the aetiology was undetermined in 174 children (73.1%). Epilepsy (15.5%) and cerebral palsy (8.4%) were the commonest associated disabilities. Conclusion The present study represents the first data on the prevalence of ID and associated disabilities in rural South African children. The prevalence of ID was comparable with results from a study performed in one other African country (Zambia) as well as those from other developing countries. The data provide an initial factual insight into ID and its associated disabilities for healthcare, social service and educational policy planners. This study provides a basis for the initiation and development of appropriate and integrated services for the best possible care of individuals affected with these disabilities, and for their possible prevention.     

The prevalence of intellectual disability among 1-year cohorts of Finnish elderly as determined with the multiple register method

Background Longevity is increasing among persons with intellectual disability (ID) simultaneously with that of the general population. There is a need to update prevalence figures of ID among the elderly. The aim of this study was to estimate the prevalence of ID among the elderly in Finland.

Method We combined data from 8 national health and social benefits registers to calculate the ID prevalence for age cohorts separated by 1-year intervals. We corrected a discontinuity due to loss of diagnostic information in the main registers at retirement age (65 years) by comparing the age distribution to that of the entire population.

Results The distribution correction more than doubled the number of persons with ID in this age group, resulting in an apparent prevalence of 0.75%.

Conclusions The 1-year interval between age cohorts proved useful in detecting discontinuities and permitted estimation. The new estimate for the prevalence of ID among the elderly is higher than those previously published, but congruent with the increasing life expectancy of elderly persons with ID.     

Aetiology of intellectual disability in paediatric outpatients in Northern India

Aim To study the aetiology of intellectual disability in patients presenting to hospital and the diagnostic yield of a standardized examination. Method Over a 1‐year period, the first three children presenting to the paediatric outpatients department (OPD) on 2 selected weekdays with developmental delay, suspected intellectual disability, or school failure were enrolled for study if they satisfied standard definitions of global developmental delay (GDD), or intellectual disability as tested by scales for Indian children: Developmental Assessment for Indian Infants, Binet Karnat Test, and the Vineland Social Maturity Scale (Malin’s Adaptation). Detailed history, and physical and neurological examinations were recorded. An algorithmic approach to investigations was followed. Also, neuroimaging, thyroid function, electroencephalograph, karyotyping, and studies for fragile‐X syndrome were conducted. Aetiological diagnosis was considered established only if clinical features were supported by investigations. Clinical features associated with a successful aetiological diagnosis were computed. Results A total of 122 children were enrolled in a cross‐sectional analytic study (mean age 43.5mo [SD 40.66]; 84 males, 38 females). Of these, a definite aetiology could be assigned in 66 children (54.1%); 17 prenatal, 38 perinatal/neonatal, and 11 postneonatal. Factors associated with reaching a definite diagnosis included younger age at presentation, presence of seizures, microcephaly, adverse neonatal events, and abnormal motor signs. Clinical history and examination gave important clues to the aetiology in 89 (72.9%) patients. Neuroimaging was abnormal in 91 out of 114 children, with aetiological findings in 48 children. Interpretation Perinatal/neonatal causes predominate as the cause of GDD or intellectual disability in India. The study highlights that a large majority of cases seen here were preventable.     

Prevalence, aetiology and comorbidity of severe and profound intellectual disability in Finland

Background The aim of the present study was to describe the aetiology, associated impairments and prevalence of severe and profound intellectual disability (SPID) in Finland. Methods The number of people with SPID in the catchment area of the Pääjärvi Centre for the Mentally Retarded, Lammi, Finland, (total population = 341 227) was calculated from the client register of this centre. Aetiological factors and background diagnoses for all subjects with SPID were analysed retrospectively. Results The number of people with SPID was 461, giving a prevalence of 0.13%. The aetiology of their SPID was genetic or congenital in 235 (50.9%) individuals, acquired in 89 (19.3%), genetic and/or acquired in 84 (18.3%), and unknown in 53 (11.5%) subjects. Out of the 53 individuals with an SPID of unknown origin, 48 (90.6%) had an associated impairment; the remaining five were the only members of the study group showing normal growth, and having neither dysmorphic features, physical abnormalities nor family members with ID. Out of the 461 subjects, 422 (91.5%) had between one and six associated impairments (total = 954), and the remaining 39 (8.5%) had SPID as their only impairment. Uncomplicated SPID was mainly of genetic or congenital origin, whereas all subjects with acquired encephalopathy had multiple disabilities. Speech defects, epilepsy and cerebral palsy were the most common associated impairments. Conclusions Severe and profound ID almost always occurs concomitantly with other severe neurological or psychiatric impairments. The proportion of people with SPID described in the present study is similar to that found in Finland in 1966. The aetiology of SPID in the vast majority of cases is biopathological.     

Prevalence and incidence of health problems in people with intellectual disability

The objective of this study was to determine the prevalence and incidence of the most frequent chronic health problems in relation to age in people with intellectual disabilities living in residential facilities in the Netherlands. A prospective cohort study was done with four data collections, each with an interval of one year. Data were collected by means of questionnaires which were completed by each person's physician. Striking results included the reported high prevalence and incidence of visual and hearing impairment, which was even more pronounced in people with Down's syndrome than in people with intellectual disability resulting from other causes. Gastrointestinal problems also appeared to have high incidence rates. Dementia was frequently reported in people with Down's syndrome aged 40 years and older. The results reflect the need for a more predictive policy which can anticipate health problems in people with intellectual disability.     

The prevalence of constipation in institutionalized people with intellectual disability

Constipation is a common problem in people with intellectual disability (ID). Laxatives are frequently prescribed with disappointing results. The prevalence of constipation was investigated in a random population of 215 people with ID (IQ < 50) and constipation was correlatead with clinical symptoms. All subjects were scored for bowel habits. Constipation was defined as having a bowel movement less than three times a week or the necessity of using laxatives more than three times a week. Further possible accompanying factors were evaluated. The control subjects were defined as individuals who did not use laxatives. Subjects with constipation were defined as patients and were compared to subjects without constipation (controls). One hundred and forty‐nine out of 215 cases (69.3%) showed constipation. Constipation was significantly correlated with non‐ambulancy, cerebral palsy, the use of anticonvulsive medication or benzodiazepines, H₂‐receptor antagonists or proton pump inhibitors, food refusal, and an IQ < 35. Fifty‐eight per cent of the patients used bisacodyl or magnesium oxide, 39% lactulose, 13% sodiumlaurylsulphoacetate/sodium citrate/sorbitol and only 10% were given sodium phosphate enemas. Faecal soiling was found in 15% of subjects, while manual evacuation of faeces was performed in nearly 7% of cases. Constipation was randomly demonstrated in almost 70% of the population with ID. Subjects with the above‐mentioned accompanying factors are especially at risk for constipation. Contrary to the general population, constipation in people with ID is associated with little use of phosphate enemas, microlax, a low incidence of faecal soiling and manual evacuation of faeces, suggesting an aetiology without distal faecal impaction. The regimen and effect of therapy has to be studied to define adequate treatment schedules.     

Contraception of women with intellectual disability: prevalence and determinants

Background The contraception of women with intellectual disability (ID) is a major concern for caregivers. However, the prevalence of contraception and the frequency of use of different methods (e.g. sterilization) remain generally unknown. Moreover, indications specific to women with ID are controversial. Methods The present authors conducted a population‐based study among 97% of the women with ID aged between 18 and 46 years attending government‐funded facilities in Brussels and the nearby province of Walloon Brabant in Belgium. Results Out of 397 subjects, 40.8% did not use any contraceptive method, 22.2% were sterilized, 18.4% used an oral contraceptive agent, 17.6% used depotmedroxyprogesterone acetate and 1% used an intrauterine device. These figures differ widely from those of the general Belgian population. Binary logistic regression for ‘contraceptive utilization’ showed the strong influence of institutional factors such as sleeping environment (i.e. institutional or parental), sexual relationship policy and contraception policy. Having or having had a boyfriend is also correlated with a stronger probability of contraceptive use. Other factors have a smaller influence (e.g. a milder level of ID). Very few factors, none of which are medical, are correlated with an increased use of a specific method. The present results are discussed in the light of the general medical application of contraception and the commonly assumed specific indications for women with ID.     

High prevalence of obesity in ambulatory children and adolescents with intellectual disability

Background   Obesity prevalence is unusually high among adults with intellectual disability (ID). There is limited and conflicting evidence on obesity prevalence among ambulatory children and adolescents with ID. The present study aimed to estimate obesity prevalence in this group and to compare with population prevalence.
Methods   Survey of nine schools ( n  = 206, 150 boys) for ambulatory children and adolescents with mild-moderate ID in Scotland in 2007. Obesity was defined as measured body mass index (BMI) at or above the 95th percentile relative to UK 1990 reference data, and using the international definition based on BMI. Obesity prevalence observed was compared against Scottish population data on obesity prevalence from the most recent nationally representative survey.
Results   Obesity prevalence (at or above 95th percentile for BMI) was 36%, and was significantly higher among those attending secondary schools compared with primary schools ( P  < 0.01). Prevalence of obesity was significantly higher than in the general paediatric population in both boys and girls ( P  < 0.01).
Conclusions   The present study suggests that that obesity may be very prevalent among ambulatory children and adolescents with ID, and that increased obesity risk may begin in childhood.     

Assessing the prevalence of intellectual disability among young male prisoners

Background   In recent years, academic debate has (re)focused on the extent of the co-occurrence of intellectual disability (ID) and criminality, although findings from prevalence studies examining this link have been inconsistent. In April 2004, a process for transferring responsibility for commissioning healthcare services in UK prisons to Primary Care Trusts (PCTs) commenced. This development meant that it was important for PCTs to ascertain the need for specialist ID services in prisons in their areas. Because there were no reliable prevalence data, this research was commissioned by one such PCT.
Method   Using a stratified random sampling frame, data were collected from 185 young adult male prisoners aged 18 and 21 years old. Participants completed a semi-structured research questionnaire, the Kaufman Brief Intelligence Test (Second Edition) (KBIT2) and the Vineland Adaptive Behavior Scales (Second Edition) (VABS2).
Results   Ten per cent had an IQ composite of 69 or below, indicating a significant impairment in cognitive functioning. A further 10% had IQ composite scores between 70 and 74, and 14% between 75 and 79. None of the sample had an Adaptive Behavior Composite (ABC) score of 69 or less, although 15% scored between 70 and 79 on this measure. While none of the sample could be classified as having an ID in strict diagnostic terms, 4% scored 69 or below on the KBIT2 and in the borderline (71–79) range on the VABS2, 4% had borderline ABCs and IQs between 70 and 74; and 3% had borderline ABCs and IQs less than 79. This equates to a point prevalence of borderline ID of 11%.
Conclusions   Eleven per cent of the sample had borderline ID, supporting suggestions that this group are prevalent – and easily hidden – in mainstream criminal justice settings. Differences between borderline ID inmates and non-ID counterparts are discussed, and implications for service delivery are considered.     

How do persons with intellectual disability manage in the open labour markets? A follow-up of the Northern Finland 1966 Birth Cohort

Background The aim was to study how many of the individuals with intellectual disability (ID; IQ ≤ 70) in an age cohort were not receiving a disability pension by the age of 34 years and what their life situation was like in terms of employment, education and morbidity. In 2000, the Northern Finland 1966 Birth Cohort (n = 12 058 live-born) included 129 individuals with ID. Method The outcome data on employment, education, pensions and morbidity were obtained from national registers. Results A total of 85.3% (n = 110) of all the individuals with ID were on pension, and 66 of them had severe ID (IQ < 50) and 44 had mild ID (IQ 50–70). Altogether 99 were drawing a pension because of ID, and 11 had a main diagnosis other than ID in the register of Social Insurance Institution. Nineteen individuals with mild ID were not on disability pension. The educational level of those without pension was low, and all whose occupation was known worked in low-level manual trades in the open labour market. During the past 8 years (1993–2000), their employment rate had been lower and unemployment rate correspondingly higher and unemployment periods longer than those of the reference group (IQ > 85 or not measured). As to the morbidity, they had been hospitalized twice more often than those in the reference group and the mean of their hospitalization days was over fourfold. Conclusion More attention should be paid to the vocational education and supported employment services of individuals with ID to help them to manage as independently as possible.     

Women with intellectual disability at risk of adverse pregnancy and birth outcomes

Background   An increasing number of women with intellectual disability (ID) have children. Cross-sectional, clinical population data suggest that these women face an increased risk of delivering preterm and/or low birthweight babies. The aim of this study was to explore the prevalence of poor pregnancy and birth outcomes in women with ID and/or self-reported learning difficulties in an antenatal population.
Methods   A total of 878 pregnant women attending their first antenatal clinic visit were 'screened' for ID. Pregnancy and birth outcomes data were extracted from medical records post-partum. These data included pregnancy-related health conditions, including pre-eclampsia and gestational diabetes, and birth outcomes, including gestational age, birthweight, Apgar score and admission to neonatal intensive care and/or special care nursery.
Results   A total of 57 (6.5%) pregnant women with ID and/or self-reported learning difficulties were identified. These women experienced an unusually high rate of pre-eclampsia (odds ratio = 2.85). Their children more often had low birthweights (odds ratio = 3.08), and they were more frequently admitted to neonatal intensive care or special care nursery (odds ratio = 2.51).
Conclusion   Further research is needed to understand the reasons for the adverse findings of this study and identify potentially changeable factors contributing to adverse pregnancy and birth outcomes for women with ID and/or self-reported learning difficulties and their children. To ensure quality antenatal care, health professionals may need to consider innovations such as extended consultation times, communication aids and audio-taping consultations.     

Mental disability among elderly men in Finland: prevalence, predictors and correlates

Mental disability, variables associated with it and predictors of mental disability in late life were studied in 716 men from eastern and southwestern Finland in connection with the 25-year follow-up of the east-west study, which formed the Finnish part of the seven-countries study. The examinations were carried out in autumn 1984, when the men were 65-84 years of age. According to a 10-item mental status questionnaire, 95% of the men had normal mental capacities. There were no differences between the 2 areas. Old age, low educational level, low functional capacity, low body mass index, low serum cholesterol, low diastolic blood pressure, low alcohol or coffee consumption, low hemoglobin, low serum calcium, low serum triiodothyronine, high scores on the Zung Self-rating Depression Scale, and presence of transient ischemia or stroke were associated with mental disability in 1984. In the prospective analysis, low forced vital capacity, low forced expiratory volume in 0.75 s and high blood pressure in middle age predicted mental disability in old age.