Joachim Knop

IQ as a Protective Factor for Subjects at High Risk for Antisocial Behavior

The current project compared the characteristics of four groups of men from a Danish birth cohort: (a) those at high risk for serious criminal involvement (with severely criminal fathers) who nevertheless succeeded in avoiding criminal behavior; (b) those at high risk who evidenced serious criminal behavior; (c) those at low risk (with noncriminal fathers) who did not evidence criminal behavior; and (d) those at low risk who nevertheless evidenced serious criminal behavior. We examined the possible role of high IQ (as tested by an abbreviated version of the Wechsler Adult Intelligence Scale) in protecting high-risk men from criminal involvement. As hypothesized, the first group evidenced a mean IQ score that was significantly higher than that of the other risk groups. The results are interpreted in terms of the reinforcing effect of success in the school system.

Alcohol use disorders increase the risk of completed suicide ― Irrespective of other psychiatric disorders. A longitudinal cohort study

Knowledge of the epidemiology of suicide is a necessary prerequisite for developing prevention programs. The aim of this study was to analyze the risk of completed suicide among individuals with alcohol use disorders (AUD), and to assess the role of other psychiatric disorders in this association. A prospective cohort study was used, containing three updated sets of lifestyle covariates and 26 years follow-up of 18,146 individuals between 20 and 93 years of age from the Copenhagen City Heart Study in Denmark. The study population was linked to four different registers in order to detect: Completed suicide, AUD, Psychotic disorders, Anxiety disorders, Mood disorders, Personality disorders, Drug abuse, and Other psychiatric disorders. Individuals registered with AUD were at significantly increased risk of committing suicide, with a crude hazard ratio (HR) of 7.98 [Confidence interval (CI): 5.27-12.07] compared to individuals without AUD. Adjusting for all psychiatric disorders the risk fell to 3.23 (CI: 1.96-5.33). In the stratified sub-sample of individuals without psychiatric disorders, the risk of completed suicide was 9.69 (CI: 4.88-19.25) among individuals with AUD. The results indicate that individuals registered with AUD are at highly increased risk of completed suicide, and that registered co-morbid psychiatric disorders are neither sufficient nor necessary causes in this association.

Comorbidity and temporal ordering of alcohol use disorders and other psychiatric disorders: results from a Danish register-based study.

BACKGROUND Understanding the comorbidity of alcohol use disorders (AUD) and other psychiatric disorders may have important implications for treatment and preventive interventions. However, information on the epidemiology of this comorbidity is lacking. The objective of this study was to present results on lifetime psychiatric comorbidity of AUD in a large Danish community population. METHODS A prospective cohort study was used, comprising 3 updated measures of sets of lifestyle covariates and 26 years of follow-up data on 18,146 individuals from the Copenhagen City Heart Study, Denmark. The study population was linked to national Danish hospital registers and a greater Copenhagen alcohol unit treatment register to detect registrations with AUD and other psychiatric disorders. RESULTS Of the individuals invited to the study, 7.6% were registered with AUD, and among these, 50.3% had a lifetime comorbid psychiatric disorder. Personality disorders were the most common comorbid disorders (24%) together with mood disorders (16.8%) and drug abuse (16.6%). The risk of developing a psychiatric disorder in individuals who were already registered with AUD was larger than the risk of developing AUD in individuals who were already registered with another psychiatric disorder; these differences in risk were especially noticeable for anxiety disorders, personality disorders, and drug abuse. CONCLUSIONS AUD is frequently comorbid with other psychiatric disorders, and it is likely that AUD is both an etiologic factor in other mental disorders and a consequence of mental disease. However, in interpreting these complex and perhaps circular causal links, it is important to consider that AUD is registered before a comorbid psychiatric diagnosis more often than the reverse temporal order.

Developmental Differences in Childhood Motor Coordination Predict Adult Alcohol Dependence: Proposed Role for the Cerebellum in Alcoholism

BACKGROUND The Danish Longitudinal Study of Alcoholism has identified a number of early biological indicators that predicted alcohol dependence 30 years later. In light of recent evidence linking deficits of the cerebellum to certain neuropsychiatric disorders often comorbid with alcoholism, we hypothesized that developmental deficits in the cerebellar vermis may also play a role in the initiation of adult alcohol dependence. The present study evaluated whether measures of motor development in the first year of life predict alcohol dependence three decades later. METHODS A total of 241 subjects of the original 330 infants who were entered into this study completed the 30-year follow-up (12 had died). The subjects were men who were drawn from a large birth cohort born in Copenhagen, Denmark, from 1959 to 1961. A comprehensive series of measures were obtained on each subject before, during, and shortly after birth as well as at 1 year of age. Muscle tone at birth and day 5 as well as 1-year measures of motor coordination--age to sitting, standing, and walking--were examined. A DSM-III-R diagnosis of alcohol dependence and a measure of lifetime problem drinking served as the 30-year outcome variables. RESULTS Several measures of childhood motor development significantly predicted alcohol dependence at 30 years of age. These included deficits in muscle tone 5 days after birth, delays in the age to sitting, and delays in the age to walking. CONCLUSIONS Relationships found between adult alcoholism and early delays in motor development offer support for the theory that cerebellar deficits may play a causal role in the addiction process.

A 30‐year follow‐up study of the sons of alcoholic men

The nature‐nurture question in the etiology of alcoholism is discussed. The research results from twin and adoption studies indicate a considerable genetic (= biological) component in the etiology of alcoholism. A longitudinal high‐risk study of alcoholism is presented. The sons of alcoholic men and matched controls have been followed prospectively since before birth. The main results from previous phases of the study and a recent 30‐year follow‐up assessment are presented.

A Danish Prospective Study of Young Males at High Risk for Alcoholism

Alcoholism represents one of the most serious health problems in modern industrialized society. In spite of persistent research efforts and preventive initiatives the main problems concerning etiology remain unsolved, while the consumption of alcohol in a society such as Denmark still increases.

Thirty-Year Follow-Up of Men at High Risk for Alcoholism

Alcoholism runs in families. This has been recognized for centuries. During much of this century it has been generally believed that “familial alcoholism” resulted from children modeling their behavior after their parents. Recent reviews of twin and adoption studies conducted in Europe and the United States indicate that alcoholism, to some extent, is influenced by Whether alcoholism is partly inherited or not, children of alcoholics are at “high risk” for alcoholism. Perhaps 20-30% of sons of alcoholics and 510% of daughters become alcoholic, a rate three to five times greater than that of the general population.’ The term “high risk study” usually refers to a study of children of afflicted families, in this case alcoholics, before they begin heavy drinking. Heavy use of alcohol may produce physical and psychological problems that can be mistaken for causal factors. The present study continues the longitudinal examination of a cohort of Danish men whose biological fathers were identified as alcoholic in a psychiatric registry or community alcohol treatment program and therefore were considered at high risk for alcoholism. The goal is to identify early predictors of future alcoholism. Predictors are not always, but sometimes, related to causation. Exploring causal factors of alcoholism is a goal of the study.

The Contribution of Parental Alcohol Use Disorders and Other Psychiatric Illness to the Risk of Alcohol Use Disorders in the Offspring

BACKGROUND Few population-based studies have investigated associations between parental history of alcoholism and the risk of alcoholism in offspring. The aim was to investigate in a large cohort the risk of alcohol use disorders (AUD) in the offspring of parents with or without AUD and with or without hospitalization for other psychiatric disorder (OPD). METHODS Longitudinal birth cohort study included 7,177 men and women born in Copenhagen between October 1959 and December 1961. Cases of AUD were identified in 3 Danish health registers and cases of OPD in the Danish Psychiatric Central Register. Offspring registration with AUD was analyzed in relation to parental registration with AUD and OPD. Covariates were offspring gender and parental social status. RESULTS Both maternal and paternal registration with AUD significantly predicted offspring risk of AUD (odds ratios 1.96; 95% CI 1.42 to 2.71 and 1.99; 95% CI 1.54 to 2.68, respectively). The association between maternal, but not paternal, OPD and offspring AUD was also significant (odds ratios 1.46; 95% CI 1.15 to 1.86 and 1.26; 95% CI 0.95 to 1.66, respectively). Other predictors were male gender and parental social status. A significant interaction was observed between paternal AUD and offspring gender on offspring AUD, and stratified analyses showed particularly strong associations of both paternal and maternal AUD with offspring AUD in female cohort members. CONCLUSIONS Parental AUD was associated with an increased risk of offspring AUD independent of other significant predictors, such as gender, parental social status, and parental psychiatric hospitalization with other diagnoses. Furthermore, this association appeared to be stronger among female than male offspring. The results suggest that inherited factors related to alcoholism are at least as important in determining the risk of alcoholism among daughters as among sons.

Paternal alcoholism predicts the occurrence but not the remission of alcoholic drinking : a 40-year follow-up

Objective:  To test the effects of fathers alcoholism on the development and remission from alcoholic drinking by age 40.

The influence of early exposure to vitamin D for development of diseases later in life

BackgroundVitamin D deficiency is common among otherwise healthy pregnant women and may have consequences for them as well as the early development and long-term health of their children. However, the importance of maternal vitamin D status on offspring health later in life has not been widely studied. The present study includes an in-depth examination of the influence of exposure to vitamin D early in life for development of fractures of the wrist, arm and clavicle; obesity, and type 1 diabetes (T1D) during child- and adulthood.Methods/designThe study is based on the fact that in 1961 fortifying margarine with vitamin D became mandatory in Denmark and in 1972 low fat milk fortification was allowed. Apart from determining the influences of exposure prior to conception and during prenatal life, we will examine the importance of vitamin D exposure during specific seasons and trimesters, by comparing disease incidence among individuals born before and after fortification. The Danish National databases assure that there are a sufficient number of individuals to verify any vitamin D effects during different gestation phases. Additionally, a validated method will be used to determine neonatal vitamin D status using stored dried blood spots (DBS) from individuals who developed the aforementioned disease entities as adults and their time and gender-matched controls.DiscussionThe results of the study will contribute to our current understanding of the significance of supplementation with vitamin D. More specifically, they will enable new research in related fields, including interventional research designed to assess supplementation needs for different subgroups of pregnant women. Also, other health outcomes can subsequently be studied to generate multiple health research opportunities involving vitamin D. Finally, the results of the study will justify the debate of Danish health authorities whether to resume vitamin D supplementation policies.