Ralf Kuja‐Halkola
Biographic Data
| ID | 9493406 |
|---|---|
| NAME | Ralf Kuja‐Halkola |
| GIVEN NAMES | Ralf |
| FAMILY NAME | Kuja‐Halkola |
| SIGNATURE | HALKOLA R K |
| AFFILIATIONS | Department of Medical Epidemiology and Biostatistics Karolinska Institutet Stockholm Sweden |
| ORCID | 0000-0002-3765-2067 |
| VERIFIED | Yes |
| TOTAL WORKS | 17 |
| TOTAL CITATIONS | 2 |
| AUTHOR COUNT | 17 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2012 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 1 |
Parental incarceration and psychiatric disorders, suicidal behavior, risk‐taking, and substance misuse events in offspring
BACKGROUND: Parental incarceration (PI) is associated with mental and behavioral problems in offspring, but causality remains unclear. We conducted a quasi-experimental within-individual study on the associations of PI with offspring psychiatric disorders, suicidal behavior, risk-taking, and substance misuse events, aiming to test the effect of PI on offspring. METHODS: The study included 43,011 and 5,912 individuals born in Sweden 1973-2010 and …
Does the family situation impact academic achievement differently in students with versus without neurodevelopmental disorders
BACKGROUND: Youth with neurodevelopmental disorders are at risk for school failure, but little is known about the contextual factors influencing academic achievement. AIMS: Drawing on a bioecological system framework, we examined how ADHD and autism, parental educational attainment and aspects of the parent-child relationship influence educational achievement at the end of primary school, and to what extent these factors have independent as oppos…
Neurodevelopmental and psychiatric conditions in 600 Swedish children with the avoidant/restrictive food intake disorder phenotype
BACKGROUND: Avoidant restrictive food intake disorder (ARFID) is a feeding and eating disorder characterized by extremely restricted dietary variety and/or quantity resulting in serious consequences for physical health and psychosocial functioning. ARFID often co-occurs with neurodevelopmental conditions (NDCs) and psychiatric conditions, but previous data are mostly limited to small clinical samples examining a narrow range of conditions. Here, …
Sex differences in psychiatric diagnoses preceding autism diagnosis and their stability post autism diagnosis
Background Autistic individuals often receive psychiatric diagnoses prior to their autism diagnosis. It remains unclear to what extent autistic females and males differ in their likelihood of receiving psychiatric diagnoses prior to their autism diagnosis and continue seeking care for them after an autism diagnosis. Methods In a nationwide cohort of all individuals born in Sweden 1990–2015 with a clinical autism diagnosis ( N = 72,331, n females …
Health, behavior, and social outcomes among offspring of parents with criminal convictions
BACKGROUND: There is currently insufficient understanding of the health and behavior of children whose parents engage in criminal behavior. We examined associations between parental criminal convictions and wide range of offspring health, behavioral, and social outcomes by age 18 in a large, national sample, aiming to get a comprehensive picture of the risks among children of offending parents. METHODS: We studied 1,013,385 individuals born in Sw…
Melatonin use and the risk of self‐harm and unintentional injuries in youths with and without psychiatric disorders
BACKGROUND: Sleep disorders in youth have been associated with increased risks of injury, including suicidal behavior. This study investigated whether melatonin, which is the most common medication for sleep disturbances in youth in Sweden, is associated with a decreased risk of injury. METHODS: This population-based cohort study included 25,575 youths who initiated melatonin treatment between ages 6 and 18. Poisson regression was used to estimat…
Adverse clinical outcomes among youths with nonsuicidal self‐injury and suicide attempts
BACKGROUND: More knowledge about risks of clinical outcomes associated with nonsuicidal self-injury (NSSI) and suicide attempts (SAs) is needed to inform risk assessment and intervention. METHODS: Longitudinal cohort study based on 1,855 youths was clinically assessed for NSSI and SA, and followed up (from December, 2011 to December 2013) for the outcomes; diagnosed self-injury, alcohol/substance use disorder, and psychiatric inpatient care data …
Perceived child impairment and the ‘autism epidemic’
BACKGROUND: The prevalence of diagnosed Autism Spectrum Disorder (ASD) has increased substantially across the world. Much - or even most - prevalence increase seems to reflect changes in diagnostic practice and ascertainment. A key part of ASD assessment is to document that the relevant symptoms are associated with clinical impairment. The aim of the present study is to capitalize on a nationwide longitudinal study spanning 15 consecutive birth y…
Familial risk and heritability of intellectual disability
BACKGROUND: Intellectual disability (ID) aggregates in families, but factors affecting individual risk and heritability estimates remain unknown. METHODS: A population-based family cohort study of 4,165,785 individuals born 1973-2013 in Sweden, including 37,787 ID individuals and their relatives. The relative risks (RR) of ID with 95% confidence intervals (95% CI) were obtained from stratified Cox proportional-hazards models. Relatives of ID indi…
Adverse perinatal events and offspring criminal convictions in men and women
We examined associations of adverse perinatal events with offspring violent and non-violent criminal convictions in men and women. All singleton births between 1973 and 1995 (n = 1,146,570 men, n = 1,085,217 women) were identified through Swedish population-based registers. Information about adverse perinatal events was retrieved from the Medical Birth Register. Outcomes were criminal convictions collected from the National Crime Register. We est…
Parental criminality and children's educational attainment
We examine how parental criminality is associated with offspring education at different educational stages from primary to tertiary education and conduct separate analyses for non-violent and violent crimes and incarceration, and for paternal and maternal criminality. We use Swedish total population register data of 513,886 children and their parents and estimate both population-level linear probability models and cousin fixed-effects models. Par…
Parental substance misuse and reproductive timing in offspring
Parents with substance misuse provide their children with a potentially risky rearing environment. According to the evolutionary life history theory, such environments steer individuals towards faster reproductive strategy. However, parents providing their children with hazardous environments may also pass on genes associated with early parenthood. In register data on individuals born in Sweden 1973–1993 (N = 2,176,128), the hazard ratio of enter…
Familial and genetic associations between autism spectrum disorder and other neurodevelopmental and psychiatric disorders
Background Familial and genetic associations between autism spectrum disorder (ASD) and other neurodevelopmental and psychiatric disorders have been reported, sometimes with conflicting results. We estimated familial and genetic associations between ASD and nine disorder groups, and explored differences in these associations for ASD in the context of intellectual disability, epilepsy, chromosomal abnormalities, and congenital malformations. Metho…
Research Review
Trajectories of healthcare utilization and costs of psychiatric and somatic multimorbidity in adults with childhood ADHD
BACKGROUND: A better understanding of the trajectories and economic burden of psychiatric and somatic disorders (multimorbidity) in ADHD from childhood to adulthood is important for guiding more targeted areas for treatment of ADHD and prevention of multimorbidity, and for forecasting demands on the medical infrastructure. This study aimed to investigate patterns of healthcare utilization and costs of multimorbidity across young adulthood in indi…
Machine‐Learning prediction of comorbid substance use disorders in ADHD youth using Swedish registry data
BACKGROUND: Children with attention-deficit/hyperactivity disorder (ADHD) have a high risk for substance use disorders (SUDs). Early identification of at-risk youth would help allocate scarce resources for prevention programs. METHODS: Psychiatric and somatic diagnoses, family history of these disorders, measures of socioeconomic distress, and information about birth complications were obtained from the national registers in Sweden for 19,787 chi…
Sibling Comparison Designs
Twins, full siblings, and half-siblings are increasingly used as comparison groups in matched cohort and matched case-control studies. The "within-pair" estimates acquired through these comparisons are free from confounding from all factors that are shared by the siblings. This has made sibling comparisons popular in studying associations thought likely to suffer confounding from socioeconomic or genetic factors. Despite the wide application of t…
Adverse perinatal events and offspring criminal convictions in men and women
We examined associations of adverse perinatal events with offspring violent and non-violent criminal convictions in men and women. All singleton births between 1973 and 1995 (n = 1,146,570 men, n = 1,085,217 women) were identified through Swedish population-based registers. Information about adverse perinatal events was retrieved from the Medical Birth Register. Outcomes were criminal convictions collected from the National Crime Register. We est…
Sibling Comparison Designs
Twins, full siblings, and half-siblings are increasingly used as comparison groups in matched cohort and matched case-control studies. The "within-pair" estimates acquired through these comparisons are free from confounding from all factors that are shared by the siblings. This has made sibling comparisons popular in studying associations thought likely to suffer confounding from socioeconomic or genetic factors. Despite the wide application of t…
Research Review
Trajectories of healthcare utilization and costs of psychiatric and somatic multimorbidity in adults with childhood ADHD
BACKGROUND: A better understanding of the trajectories and economic burden of psychiatric and somatic disorders (multimorbidity) in ADHD from childhood to adulthood is important for guiding more targeted areas for treatment of ADHD and prevention of multimorbidity, and for forecasting demands on the medical infrastructure. This study aimed to investigate patterns of healthcare utilization and costs of multimorbidity across young adulthood in indi…
Machine‐Learning prediction of comorbid substance use disorders in ADHD youth using Swedish registry data
BACKGROUND: Children with attention-deficit/hyperactivity disorder (ADHD) have a high risk for substance use disorders (SUDs). Early identification of at-risk youth would help allocate scarce resources for prevention programs. METHODS: Psychiatric and somatic diagnoses, family history of these disorders, measures of socioeconomic distress, and information about birth complications were obtained from the national registers in Sweden for 19,787 chi…
Parental substance misuse and reproductive timing in offspring
Parents with substance misuse provide their children with a potentially risky rearing environment. According to the evolutionary life history theory, such environments steer individuals towards faster reproductive strategy. However, parents providing their children with hazardous environments may also pass on genes associated with early parenthood. In register data on individuals born in Sweden 1973–1993 (N = 2,176,128), the hazard ratio of enter…
Familial and genetic associations between autism spectrum disorder and other neurodevelopmental and psychiatric disorders
Background Familial and genetic associations between autism spectrum disorder (ASD) and other neurodevelopmental and psychiatric disorders have been reported, sometimes with conflicting results. We estimated familial and genetic associations between ASD and nine disorder groups, and explored differences in these associations for ASD in the context of intellectual disability, epilepsy, chromosomal abnormalities, and congenital malformations. Metho…
Adverse clinical outcomes among youths with nonsuicidal self‐injury and suicide attempts
BACKGROUND: More knowledge about risks of clinical outcomes associated with nonsuicidal self-injury (NSSI) and suicide attempts (SAs) is needed to inform risk assessment and intervention. METHODS: Longitudinal cohort study based on 1,855 youths was clinically assessed for NSSI and SA, and followed up (from December, 2011 to December 2013) for the outcomes; diagnosed self-injury, alcohol/substance use disorder, and psychiatric inpatient care data …
Perceived child impairment and the ‘autism epidemic’
BACKGROUND: The prevalence of diagnosed Autism Spectrum Disorder (ASD) has increased substantially across the world. Much - or even most - prevalence increase seems to reflect changes in diagnostic practice and ascertainment. A key part of ASD assessment is to document that the relevant symptoms are associated with clinical impairment. The aim of the present study is to capitalize on a nationwide longitudinal study spanning 15 consecutive birth y…
Familial risk and heritability of intellectual disability
BACKGROUND: Intellectual disability (ID) aggregates in families, but factors affecting individual risk and heritability estimates remain unknown. METHODS: A population-based family cohort study of 4,165,785 individuals born 1973-2013 in Sweden, including 37,787 ID individuals and their relatives. The relative risks (RR) of ID with 95% confidence intervals (95% CI) were obtained from stratified Cox proportional-hazards models. Relatives of ID indi…
Adverse perinatal events and offspring criminal convictions in men and women
We examined associations of adverse perinatal events with offspring violent and non-violent criminal convictions in men and women. All singleton births between 1973 and 1995 (n = 1,146,570 men, n = 1,085,217 women) were identified through Swedish population-based registers. Information about adverse perinatal events was retrieved from the Medical Birth Register. Outcomes were criminal convictions collected from the National Crime Register. We est…
Parental criminality and children's educational attainment
We examine how parental criminality is associated with offspring education at different educational stages from primary to tertiary education and conduct separate analyses for non-violent and violent crimes and incarceration, and for paternal and maternal criminality. We use Swedish total population register data of 513,886 children and their parents and estimate both population-level linear probability models and cousin fixed-effects models. Par…
Melatonin use and the risk of self‐harm and unintentional injuries in youths with and without psychiatric disorders
BACKGROUND: Sleep disorders in youth have been associated with increased risks of injury, including suicidal behavior. This study investigated whether melatonin, which is the most common medication for sleep disturbances in youth in Sweden, is associated with a decreased risk of injury. METHODS: This population-based cohort study included 25,575 youths who initiated melatonin treatment between ages 6 and 18. Poisson regression was used to estimat…
Health, behavior, and social outcomes among offspring of parents with criminal convictions
BACKGROUND: There is currently insufficient understanding of the health and behavior of children whose parents engage in criminal behavior. We examined associations between parental criminal convictions and wide range of offspring health, behavioral, and social outcomes by age 18 in a large, national sample, aiming to get a comprehensive picture of the risks among children of offending parents. METHODS: We studied 1,013,385 individuals born in Sw…
Neurodevelopmental and psychiatric conditions in 600 Swedish children with the avoidant/restrictive food intake disorder phenotype
BACKGROUND: Avoidant restrictive food intake disorder (ARFID) is a feeding and eating disorder characterized by extremely restricted dietary variety and/or quantity resulting in serious consequences for physical health and psychosocial functioning. ARFID often co-occurs with neurodevelopmental conditions (NDCs) and psychiatric conditions, but previous data are mostly limited to small clinical samples examining a narrow range of conditions. Here, …
Sex differences in psychiatric diagnoses preceding autism diagnosis and their stability post autism diagnosis
Background Autistic individuals often receive psychiatric diagnoses prior to their autism diagnosis. It remains unclear to what extent autistic females and males differ in their likelihood of receiving psychiatric diagnoses prior to their autism diagnosis and continue seeking care for them after an autism diagnosis. Methods In a nationwide cohort of all individuals born in Sweden 1990–2015 with a clinical autism diagnosis ( N = 72,331, n females …
Parental incarceration and psychiatric disorders, suicidal behavior, risk‐taking, and substance misuse events in offspring
BACKGROUND: Parental incarceration (PI) is associated with mental and behavioral problems in offspring, but causality remains unclear. We conducted a quasi-experimental within-individual study on the associations of PI with offspring psychiatric disorders, suicidal behavior, risk-taking, and substance misuse events, aiming to test the effect of PI on offspring. METHODS: The study included 43,011 and 5,912 individuals born in Sweden 1973-2010 and …
Does the family situation impact academic achievement differently in students with versus without neurodevelopmental disorders
BACKGROUND: Youth with neurodevelopmental disorders are at risk for school failure, but little is known about the contextual factors influencing academic achievement. AIMS: Drawing on a bioecological system framework, we examined how ADHD and autism, parental educational attainment and aspects of the parent-child relationship influence educational achievement at the end of primary school, and to what extent these factors have independent as oppos…
Psychology (14 works) · Medicine (11 works) · Psychiatry (10 works) · Population (8 works) · Clinical Psychology (7 works) · Demography (6 works) · Pediatrics (6 works) · Pediatrics (6 works) · Family and Disability Support Research (5 works) · Injury prevention (5 works)