Statistics in Medicine: Calculating confidence intervals for relative risks (odds ratios) and standardised ratios and rates

Morris, Julie; Gardner, Martin J.

doi:10.1136/bmj.296.6632.1313

Cited by 747 publications

(451 citation statements)

References 17 publications

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“…Univariate analyses included chisquare statistic and Student's t test. The rate ratios and 95 % confidence intervals for incidence of severe visual impairment were estimated by baseline variables [8] using the MantelHaenszel test for bivariate analyses [9] and stepwise linear logistic regression for multivariate analyses [10]. A p value of less than 0.05 was considered statistically significant.…”

Section: Methodsmentioning

confidence: 99%

The incidence of visual impairment and its determinants in the WHO multinational study of vascular disease in diabetes

Miki

Lee

et al. 2001

Diabetologia

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In industrial societies more than 12 % of new cases of blindness are attributable to diabetes and the risk of blindness is about 30 times higher in people with diabetes than in the general population [1,2, 3]. The WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD), designed to compare the vascular complications of diabetes in different ethnic groups using standardised methods, included an estimate of visual function in the baseline assessment [28]. This was repeated in the follow-up study [4], conducted at 10 of the original 14 centres, providing an opportunity to ascertain incidence and progression of visual impairment and its risk factors in these cohorts. Diabetologia (2001) Methods. Visual function was ascertained at followup in 2994 (77.9 %) of the 3845 eligible participating survivors of the 4709 originally recruited for the WHO MSVDD using the same baseline enquiry method. The associations between incident severe visual impairment, follow-up prevalence of all grades of impairment and baseline risk factors were examined by univariate and stepwise multiple logistic regression analysis. Results. Overall, 8.4 year incidence of severe visual impairment was 1.94 % and showed statistically significant univariate correlations with age at diagnosis, diabetes duration, systolic blood pressure, fasting blood glucose and cholesterol, insulin treatment and strongly with baseline retinopathy. Baseline retinopathy, systolic pressure and cholesterol were statistically significant in multivariable analysis. Differences between centres (0.3 % to 3.45 %) were not significant. Ultimate prevalence of all grades of impairment differed between centres and within almost all of them was correlated in multivariable analysis with baseline retinopathy and proteinuria. Conclusion/interpretation. Comparisons of incident severe visual impairment between centres are restricted by selective mortality, low incidence rates and relatively small numbers in each centre but before retinopathy, baseline systolic pressure and cholesterol predicted severe visual impairment. Followup prevalence of all degrees of impairment varied among centres and were associated with prior retinopathy and renal disease at baseline. [Diabetologia (2001)

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Section: Methodsmentioning

confidence: 99%

The incidence of visual impairment and its determinants in the WHO multinational study of vascular disease in diabetes

Miki

Lee

et al. 2001

Diabetologia

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“…This approach provided SNP allele-or haplotype-specific nominal significance levels. Odds ratios (OR) were computed using the method of Morris and Gardner, 86 with the logit method used to calculate the OR of the combined Portuguese trios and case-control sample.…”

Section: Genotypingmentioning

confidence: 99%

Genetic investigation of chromosome 5q GABAA receptor subunit genes in schizophrenia

et al. 2005

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We previously performed a genome-wide linkage scan in Portuguese schizophrenia families that identified a risk locus on chromosome 5q31-q35. This finding was supported by metaanalysis of 20 other schizophrenia genome-wide scans that identified 5q23.2-q34 as the second most compelling susceptibility locus in the genome. In the present report, we took a two-stage candidate gene association approach to investigate a group of gamma-aminobutyric acid (GABA) A receptor subunit genes (GABRA1, GABRA6, GABRB2, GABRG2, and GABRP) within our linkage peak. These genes are plausible candidates based on prior evidence for GABA system involvement in schizophrenia. In the first stage, associations were detected in a Portuguese patient sample with single nucleotide polymorphisms (SNPs) and haplotypes in GABRA1 (P ¼ 0.00062-0.048), GABRP (P ¼ 0.0024-0.042), and GABRA6 (P ¼ 0.0065-0.0088). The GABRA1 and GABRP findings were replicated in the second stage in an independent German family-based sample (P ¼ 0.0015-0.043). Supportive evidence for association was also obtained for a previously reported GABRB2 risk haplotype. Exploratory analyses of the effects of associated GABRA1 haplotypes on transcript levels found altered expression of GABRA6 and coexpressed genes of GABRA1 and GABRB2. Comparison of transcript levels in schizophrenia patients and unaffected siblings found lower patient expression of GABRA6 and coexpressed genes of GABRA1. Interestingly, the GABRA1 coexpressed genes include synaptic and vesicle-associated genes previously found altered in schizophrenia prefrontal cortex. Taken together, these results support the involvement of the chromosome 5q GABA A receptor gene cluster in schizophrenia, and suggest that schizophrenia-associated haplotypes may alter expression of GABA-related genes.

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“…9 The standardised mortality ratio (SMR), the ratio between the observed and the expected numbers, was calculated with 95% confidence intervals (95% CIs) assuming a Poisson distribution. 10 …”

Section: Methodsmentioning

confidence: 99%

Female seafarers adopt the high risk lifestyle of male seafarers.

Hansen¹,

Jensen²

1998

Occup Environ Med

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Objective-To study the mortality of women in an occupation known to have a high mortality among men. Methods-A total of 6788 female seafarers of all job categories who had been employed on Danish merchant ships, passenger ships, and privately owned ferries between 1986 and 1993, were followed up until the end of 1993. Results-Standardised mortality ratio (SMR) was 1.20 (95% confidence interval (95% CI) 0.89 to 1.58) for all causes of death and job categories together. For women in traditionally male jobs, SMR was 2.82 (1.41-5.05), whereas galley and catering staV had SMRs close to the general female population. The high mortality among women in traditional male jobs could be explained by a high risk of fatal accidents including occupational accidents. In the whole cohort, there were fewer deaths from natural causes than expected but an excess risk of death due to lung cancer, heart diseases, and nonnatural deaths. Conclusion-The increased mortality could primarily be explained by an excess risk of fatal accidents and suicide. Especially, female seafarers entering traditional male jobs had a high risk of fatal accidents, not only at sea but also ashore. An excess risk of dying of lung cancer and heart diseases probably reflects a high tobacco consumption. Female seafarers are probably influenced by their occupation towards hazardous behaviour and a high risk lifestyle but people with a high risk lifestyle may also be attracted by or forced into high risk jobs such as traditional male jobs at sea. (Occup Environ Med 1998;55:49-51)

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Statistics in Medicine: Calculating confidence intervals for relative risks (odds ratios) and standardised ratios and rates

Cited by 747 publications

References 17 publications

The incidence of visual impairment and its determinants in the WHO multinational study of vascular disease in diabetes

The incidence of visual impairment and its determinants in the WHO multinational study of vascular disease in diabetes

Genetic investigation of chromosome 5q GABAA receptor subunit genes in schizophrenia

Female seafarers adopt the high risk lifestyle of male seafarers.

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