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PubMed1987

Choice of control population in studies of adverse reproductive effects of occupational exposures and its effect on risk estimates.

Cohort studies of adverse reproductive effects of occupational exposures that compare the outcome of exposed pregnancies with non-exposed pregnancies among the same group of mothers (internal controls) and among a different group of mothers (external controls) have been reviewed. Confounding of the hypothesised associations by parental characteristics, the outcome of previous pregnancies, and other exposures is not adequately assessed in these studies. The risk of an adverse outcome appears to be consistently higher among the external control group of pregnancies than among the internal controls. If the differences between the two control groups are real, comparisons based on external controls underestimate the relative or attributable risk. Alternative explanation for this phenomenon are discussed. A likely explanation is a misclassification of exposure or a high prevalence of risk factors other than the exposure of interest among the external controls. Non-exposed pregnancies among exposed mothers may be used for comparison in preference to pregnancies among non-exposed mothers.

Abortion, Spontaneous↗
PubMedDate not supplied

[Tridimensional Personality Questionnaire (TPQ): validation in a French-speaking control population].

Among the dimensional scales that measure personality, Cloninger's TPQ (Tridimensional Personality Questionnaire) holds a place apart in the literature, because the hypotheses it relies on are partially biological. The questionnaire (100 forced binary items) includes three axes: "Novelty Seeking", "Harm Avoidance" and "Reward Dependence", each theoretically bound to a preferential neuromediator, respectively dopamine, serotonin and norepinephrine. Each axis includes four minor subscales. The study presented here is the analysis of 104 control volunteers from both genders (59 males). This database is the first to be published with a French-speaking population. The comparison with Cloninger's normative database shows many similarities: the mean values for the 3 axes are relatively close. The population studied here is younger and this factor could play a role in the somewhat higher mean novelty seeking scores found here. The three axes show a normal distribution. Skewness and kurtosis are between -1 and +1 for all the subscales, except here for NS2. Factorial structure is quite similar to Cloninger's results. The three first axes correspond to the variables isolated in the first studies and the fourth one includes the same subscales as in the large American database. Inverse correlation between age and novelty seeking, positive correlation between female gender and harm avoidance and reward dependence were also found. However, no correlation was found between novelty seeking and male gender. A correlation was found between level of instruction and NS1 only, not with the whole NS axis. Eighty-seven % of volunteers presented with at least one standard deviation on at least one axis and 68% on at least two. This does not seem to have been described previously. It can be a sign of the difficulty of human beings to show a balanced personality. In conclusion, the database presented here shows many similarities with Cloninger's normative database. This underscores its value for comparisons in clinical trials in the future.

Adult↗
PubMed1971

Population control potential of heterozygous translocations as determined by computer simulations.

A possible method for genetic control of insect vector species involves the use of translocation heterozygotes. The potential of single and double heterozygotes already available in Aedes aegypti has been investigated with computer simulations of release strategies. Such simulations indicate a possible role for translocation heterozygotes of these types in an insect population characterized by a 5-fold population growth per generation, or less.

Aedes↗
PubMed1989

Cytogenetical studies on a large control population and on persons occupationally exposed to radiation and/or to chemicals.

Nowadays all people are exposed to mutagens environmentally, occupationally, therapeutically or due to life style. In order to validate any conclusions concerning a possible effect of some kind of these mutagens to the relevant exposed groups, chromosomal analysis was carried out on a standard population (211 persons) distributed randomly from biological and social points of view and on 163 persons, occupationally exposed to different kinds of mutagens. Analysis proved that the mean frequency of chromosomal aberrations (CA) of control was 0.81% and it was similar before and following the Chernobyl events. Data concerning the CA frequency in people exposed occupationally to low doses of ionizing radiations below the internationally accepted permissible level, showed a 2-6-fold increase of aberrant cells. Occupational exposure to chemical mutagens such as vinyl-chloride and organic solvents like benzene and toluene revealed 2-4 times higher frequency of CAs than the control; however, exposures to organophosphorus insecticides reached a 5-6-fold increase in CAs as well. The sister chromatid exchange (SCE) frequency data were in each exposed group higher than the control values. Neither chromosomal aberration frequencies, nor sister chromatid exchanges differed significantly between smokers and non smokers in control and exposed persons.

Adult↗
PubMed2006

RGS4 is not a susceptibility gene for schizophrenia in Japanese: association study in a large case-control population.

The regulator of the G-protein signaling 4 (RGS4) has been implicated in the susceptibility to schizophrenia. RGS4 interacts with ErbB3 that acts as receptors for neuregulin 1 and these proteins may play a role in the pathogenesis of schizophrenia via glutamatergic dysfunction. Recently, two meta-analysis studies provided different interpretations for the genetic association between RGS4 and schizophrenia. We attempted to confirm this association in a case-control study of 1918 Japanese patients with schizophrenia and 1909 Japanese control subjects. Four widely studied single nucleotide polymorphisms (SNPs) were genotyped, and none showed association with schizophrenia. SNP 1 (rs10917670), p=0.92; SNP 4 (rs951436), p=0.91; SNP 7 (rs951439), p=0.27; and SNP 18 (rs2661319), p=0.43. A haplotype block constructed by these SNPs spans the 5' flanking region to the 5' mid-region of the RGS4 gene. Previous meta-analysis showed that both two major haplotypes of this block were risk haplotypes. The two common haplotypes were observed in the Japanese population. However, neither haplotype was significantly associated with schizophrenia. We conclude that the common haplotypes and SNPs of the RGS4 gene identified thus far are unlikely to contribute to the genetic susceptibility to schizophrenia in the Japanese population.

Adult↗
PubMed1993

The relationship between the prevalence of uterine lesions and the use of medroxyprogesterone acetate for canine population control.

The prevalence of uterine disease was established during desexing of 175 bitches in the Torres Strait and Cape York, 42 of which had been treated with injectable medroxyprogesterone acetate (MPA) for oestrus postponement. The prevalence of uterine lesions was 45% for treated bitches, 5% for untreated bitches, and 14.9% for the sample population. A highly significant relationship (P < 0.01) between MPA treatment and uterine lesions was established. A significant association (P < 0.05) between age (> 2 years old) and uterine lesions was found, most likely attributable to a significantly higher proportion (P < 0.01) of MPA-treated bitches in the older population. There was no significant difference in the effect of MPA on the prevalence of uterine lesions between older and younger bitches. There was no effect of parity on the prevalence of uterine lesions.

Animals↗
PubMed1992

[Cleft lip and cleft palate: cephalometric characteristics of affected individuals, their relatives and a control population].

Eight cephalometric parameters were determined in individuals affected with cleft lip and cleft palate, their parents and siblings and a sample of normal individuals. No differences were found in males in any group. In contrast, affected females had lower measurements than their female relatives, and these lower latter in turn had measurements than control females. Although differences between groups were significant enough overlap existed and therefore genetic counseling based on these measurements would be uncertain.

Adolescent↗
PubMed2003

The Johns Hopkins telephone diagnostic interview for the restless legs syndrome: preliminary investigation for validation in a multi-center patient and control population.

STUDY OBJECTIVES: To develop and validate a telephone diagnostic interview (the Johns Hopkins telephone diagnostic interview for restless legs, abbreviated TDI) for diagnosis of the restless legs syndrome (RLS). DESIGN AND METHODS: Using the International RLS Study Group diagnostic criteria, specific questions were developed reflecting the diagnostic features of RLS. Seventy-five subjects (37 previously diagnosed RLS patients and 38 controls self-reported to be free of RLS) were interviewed by three expert interviewers blinded to each others' interviews and the patient's clinical status. The interviewers diagnosed each subject based on responses to the TDI. RESULTS: The interviewers overall correctly diagnosed 72 of 75 individuals. Minimum interviewer sensitivity and specificity were 97 and 92%, respectively. The intraclass correlation coefficient (ICC) was used to quantify inter-rater reliability for the three interviewers. The ICC for diagnosis was 0.95. The ICC calculated on other key items in the interview exceeded 0.80 in all cases. The patients were predominantly older individuals with long-standing RLS; 19 of them scored at the highest level of severity on the Johns Hopkins Restless Legs Severity Scale (JHRLSS). The interviewers had more difficulty with assessing the controls accurately, some of whom were probably incorrectly self-categorized as not having RLS. CONCLUSIONS: The TDI is a sensitive, specific, and reliable instrument for diagnosing RLS by experienced interviewers in a brief, anonymous telephone encounter.

Adult↗
PubMed2004

Fracture risk of women with primary biliary cirrhosis: no increase compared with general population controls.

AIM: Patients with primary biliary cirrhosis may be at increased risk of osteoporosis but to what extent this is reflected in an increased fracture risk is unknown. We have enquired about the fracture experience of female primary biliary cirrhosis patients compared with sex- and age-matched controls. METHODS: Patients aged 30-75 with primary biliary cirrhosis and age-matched controls were sent a postal questionnaire asking about their fracture history and details of risk factors for osteoporosis. RESULTS: 85 eligible patients with primary biliary cirrhosis and 116 controls responded. Forty-one per cent of patients with primary biliary cirrhosis and 30% of controls reported ever having had a fracture odds ratio 1.5 (95% confidence interval: 0.80-2.89). Twenty-eight per cent of primary biliary cirrhosis patients and 23.3% of controls reported a fracture after the age of 30, odds ratio 1.2 (95% confidence interval: 0.57-2.56), and 14.1% of primary biliary cirrhosis patients and 12.1% of controls reported a low impact fracture of the long bones or of the vertebrae odds ratio 1.0 (95% confidence interval: 0.31-2.68). CONCLUSIONS: No overall increased fracture risk in patients with primary biliary cirrhosis was observed. As a group, unselected patients with primary biliary cirrhosis do not represent a population at particularly high risk of osteoporotic fracture and thus targeting them for osteoporosis screening and treatment is not justified. Further work investigating subgroups of patients with primary biliary cirrhosis at potentially high risk of osteoporosis, such as those with advanced disease or severe cholestasis is required.

Adult↗