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Biomedical subjects

Jari Haukka

Publications and source records attributed to Jari Haukka.

8 recordsLinked to original sources
PubMed2003

Familial loading associates with impairment in visual span among healthy siblings of schizophrenia patients.

BACKGROUND: The effect of familial loading on neurocognitive deficits in relatives of schizophrenia patients has been detected in family and twin studies. The present study examined this effect among healthy siblings of schizophrenia patients in a Finnish isolate with high prevalence of schizophrenia. METHODS: We assessed performance in verbal and visual span tasks, in tests measuring intelligence, and in declarative verbal memory and learning tasks in 31 and 67 healthy siblings from families with one schizophrenia patient, or with two or more patients, respectively. The differences between the groups were tested using linear mixed effects models. RESULTS: An effect of familial loading was detected in the backward visual span task, measuring immediate visual memory with requirements from the visual domain of working memory. In this task, the healthy siblings from multiply affected families performed worse than those from the singleton families. CONCLUSIONS: The finding that the multiplex vs. singleton differences were selective to the backward visual span task, strengthens the view that the visual domain of working memory may provide a valuable endophenotypic marker for genetic schizophrenia studies.

Adult↗
PubMed2003

Increasing age does not decrease risk of schizophrenia up to age 40.

It is well established that at the population level the age-specific incidence of schizophrenia is highest in the early 20s and decreases with age. We present new findings showing that this is not the case when we assume that only part of the population is susceptible. The study population consisted of birth cohorts born in Finland from 1950 to 1968. These were identified from the Population Register Center, which provided the data as multidimensional tables with sex, and year, month, and place of birth as marginals. Each cohort was followed-up until 1991, up to age 40. Data analyses were based on a compound Poisson statistical model, which assumed that only part of the population is susceptible to develop schizophrenia. The method detects the proportion of susceptibles in population level, but does not identify susceptible individuals. The model was able to reveal the basic hazard distribution, which showed increasing risk of developing schizophrenia with higher age at the individual level among the susceptible part of the population. The increase in risk was more rapid among males, but the susceptible part of the population was of similar size among both sexes. The proportion of susceptibles seemed to be lower in younger cohorts. We conclude that when an individual belongs to the susceptible part of the population, his/her individual risk of developing schizophrenia increases with age, at least up to age 40. This increase is more rapid among males. The reasons behind the lower proportion of susceptibles in younger birth cohorts, as well reasons for differences in risk between sexes remained unclear and need more research.

Adult↗
PubMed2003

Association of dietary amino acids with low mood.

Diet may affect mood and cognitive functions. Tryptophan and serine augmentation strategies have been applied for patients with mood or psychotic disorders. We studied the association between dietary intake of amino acids and low mood. We studied 29,133 men aged 50-69 years for 5-8 years in a population-based trial in Finland. Intake of amino acids was calculated from a diet history questionnaire completed by 27,111 men at baseline. Self-reports of depressed mood were recorded thrice a year, data on hospital treatment due to depressive disorders were derived from the national Hospital Discharge Register, and suicides were identified from death certificates. Participants were smokers at study entry. Strengths of our study include detailed data on food consumption, a substantial number of study participants, a long prospective follow-up time, and versatile data on indices of low mood. We found no association between the dietary intake of amino acids and self-report of depressed mood or risk of suicide. However, dietary intake of lysine and serine was associated with risk of hospital treatment due to major depressive disorder but these associations disappeared after excluding from analysis those who had reported depressed mood at study entry. There is no consistent association between dietary intake of amino acids and low mood.

Aged↗
PubMed2003

Fertility of patients with schizophrenia, their siblings, and the general population: a cohort study from 1950 to 1959 in Finland.

OBJECTIVE: Genetic factors are the most important risk factors for schizophrenia. However, despite the fact that patients with schizophrenia have significantly fewer offspring than the general population, schizophrenia persists. The authors investigated whether the siblings of patients with schizophrenia produce more offspring, thereby compensating for the low fertility of the affected individuals. METHOD: From all 870,093 individuals born in Finland from 1950 to 1959, the authors determined how many had schizophrenia or were siblings of schizophrenia patients and how many offspring they had. The population data were obtained from the Population Register Center of Finland, and the National Hospital Discharge Register was used to identify all persons who had been hospitalized because of schizophrenia. Appropriate regression models were used to model age at the birth of the first child, number of children, and proportion of males among offspring. RESULTS: Of the total population, 1.3% were patients with schizophrenia, and 2.8% were their siblings. The mean number of offspring among female siblings was slightly but significantly higher than among women in the general population (1.89 versus 1.83), while the opposite was true for the male siblings (1.57 versus 1.65 among men in the general population). The mean number of offspring among patients with schizophrenia was 0.83 for women and 0.44 for men. CONCLUSIONS: Lower than average fertility among patients with schizophrenia is not compensated for by higher fertility among their siblings. Thus, the persistence of schizophrenia in the general population is not explained by this simple evolutionary mechanism.

Adult↗
PubMed2003

Childhood central nervous system viral infections and adult schizophrenia.

OBJECTIVE: An earlier Finnish cohort study suggested that childhood viral CNS infections are associated with a fivefold increased odds of developing schizophrenia in adulthood. The authors sought to replicate this finding. METHOD: From the archives of the Department of Virology of the National Public Health Institute in Finland, 320 individuals born between 1960 and 1976 who had suffered virologically confirmed CNS infections before their 15th birthdays were identified. Of the infections, 202 had been caused by enteroviruses. The sample was followed up in the 1969-2000 records of the National Hospital Discharge Register of Finland to identify all cases of schizophrenia that emerged. RESULTS: The cumulative incidence of schizophrenia was 0.94% in the whole sample and 0.99% among individuals who had suffered enteroviral infections. These rates are comparable to that found in the general population. CONCLUSIONS: Childhood viral CNS infections were not associated with increased risk of schizophrenia.

Adolescent↗
PubMed2003

Timed bright-light exposure and complaints related to shift work among women.

OBJECTIVES: This field study measured whether repeated, brief exposures to bright light during night shifts improved subjective well-being during and after night work. A secondary objective was to investigate whether this response differed by season (summer or winter), seasonality, or age. METHODS: Eighty-seven healthy female nurses were voluntarily exposed to brief periods (4 x 20 minutes) of bright (5000 lux) light at scheduled times during every night shift over a 2-week period. Each morning following a night shift the subjects filled out self-assessment questionnaires measuring subjective symptoms and distress caused by work at night. The questionnaires were also completed 2 weeks before and after the light intervention. The study had two phases, summer (May-June) and winter (November-December). Thirty-seven of the subjects participated during both periods. RESULTS: Light significantly alleviated the subjective distress associated with nightshift work, both in summer and in winter, independent of the subject's age. The effect was stronger for those who reported routine seasonal changes in mood. CONCLUSIONS: Short pulses of timed bright-light exposure may enhance subjective adaptation to night work.

Adaptation, Psychological↗
PubMed2002

Heritability and number of quantitative trait loci of neurocognitive functions in families with schizophrenia.

Despite evidence for several chromosomal loci linked to schizophrenia, no susceptibility genes have been identified for the disorder. Using quantitative measures of phenotypic affection in place of clinical diagnostic categories or dichotomous classification of the affection status may be more effective in searching for susceptibility genes. Neurocognitive traits have been suggested as putative quantitative endophenotypes of the disorder, but their heritability estimates are not well known. We investigated the heritability of working memory, verbal declarative memory and its different components, and both verbal and visual ability functions in schizophrenia families with a well-ascertained pedigree structure. We also estimated the number of quantitative trait loci (QTLs) contributing to these neurocognitive functions. Additive genetic heritability of the neurocognitive functions was estimated in a sample of schizophrenia patients and their first-degree relatives (N = 264) from an isolated geographical subregion in Finland. The number of QTLs was analyzed using Markov chain Monte Carlo segregation analysis. Significant heritabilities were found in working memory and ability functions. Furthermore, the working memory functions revealed the most restricted number of QTLs. The mean numbers of loci for verbal and visual working memory were 1.2 and 1.0, respectively, with corresponding posterior probabilities of 73% and 70% for at least one locus. In declarative memory variables, the number of loci was more dispersed. Our results suggest that neurocognitive measures, particularly working memory, may provide valid quantitative phenotypic traits for linkage analyses searching predisposing genes for schizophrenia.

Adult↗