Obstetric complications in patients with depression--a population-based case-control study

BACKGROUND: To examine whether sufferers of affective disorders are more likely to be subject to obstetric complications than normal healthy people. METHOD: Data based on prospectively recorded birth case-notes for patients with a diagnosis of depression (or related disorders) with early onset were compared to those of normal healthy controls, individually matched by gender, time and parity of birth, maternal age and marital status. RESULTS: Forty-one case-controls pairs born between 1964 and 1978 were compared. No differences between cases and controls in gestational age or birthweight were significant, though depressive patients on average weighed 200 g less than controls at birth. Patients were more likely than controls to be small for their gestational age (22 vs. 1: chi(2)=4.34, P=0.03). They were significantly more likely than controls to have suffered at least one obstetric complication: 35 (85%) vs. 25 (60%), chi(2)=5.03, P=0.02; or more than one (two on average, as opposed to one on average among controls). No obstetric complication was seen significantly more among cases than controls, apart from bleeding during gestation, which was observed for four cases and no controls. The prevalence of complications with a clear brain damaging potential did not differ significantly between cases and controls: 11 (26%) vs. 8 (19%). CONCLUSIONS: A developmental deficit, as indicated by lower birthweight and gestational age, may contribute to the risk of depressive breakdowns and affective disorders in later life. Severe, brain damaging obstetric complications are unlikely to be a significant risk factor for affective disorders, though some early onset cases may be accounted for by prenatal brain lesions. Limitations: Sample size limits statistical power for isolation of a rare, single risk factor.     

Are spouses of patients with hypertension at increased risk of having hypertension? A population-based case-control study.

BACKGROUND: Studies of couples, who tend to share an environment but are genetically dissimilar, can shed light on the contribution of environmental factors to hypertension. There has been renewed interest in these environmental factors following the re-analysis of the INTERSALT study. AIM: To determine whether patients whose spouses have hypertension are at increased risk of hypertension, using a population-based case-control study. METHOD: The total study population consisted of all 3923 patients over 30 years old registered with one general practice. Male cases with hypertension were matched to male controls without hypertension. Female cases with hypertension were matched to female controls without hypertension. The variables were: diagnosed hypertension; having a spouse with diagnosed hypertension; age; sex; weight; height; body-mass index; couple status; diabetes; and systolic and diastolic blood pressure readings. RESULTS: On multivariate analysis, when age, body-mass index, diabetes, couple status, and having a blood pressure reading were included, men whose spouses had hypertension had a two-fold increased risk of hypertension (adjusted odds ratio (OR) 2.24; 95% CI 1.77-2.72; P = 0.001). Similarly, on multivariate analysis, women whose spouses had hypertension had a two-fold increased risk of hypertension (adjusted OR = 2.23; 95% CI 1.75-2.72; P = 0.001). The risk for both male and female subjects persisted after adjustment for other variables. There was a significant correlation between systolic (r = 0.41; P < 0.0001) and diastolic (r = 0.25; P < 0.0001) blood pressures between spouse pairs. CONCLUSION: The independent association between having a spouse with hypertension and increased risk of hypertension supports the view that there are significant environmental factors in the aetiology of hypertension. The finding has implications for the screening and treatment of hypertension in primary care.     

Risk of childhood cancer with symptoms in primary care: a population-based case-control study

Background

Guidelines describing symptoms in children that should alert GPs to consider cancer have been developed, but without any supporting primary-care research.

Aim

To identify symptoms and signs in primary care that strongly increase the likelihood of childhood cancer, to assist GPs in selection of children for investigation.

Design and setting

A population-based case-control study in UK general practice.

Method

Using electronic primary care records from the UK General Practice Research Database, 1267 children aged 0–14 years diagnosed with childhood cancer were matched to 15 318 controls. Clinical features associated with subsequent diagnosis of cancer were identified using conditional logistic regression, and likelihood ratios and positive predictive values (PPVs) were estimated for each.

Results

Twelve symptoms were associated with PPVs of ≥0.04%, which represents a greater than tenfold increase in prior probability. The six symptoms with the highest PPVs were pallor (odds ratio, OR = 84; PPV = 0.41% (95% confidence interval [CI] = 0.12% to 1.34%), head and neck masses (OR = 17; PPV = 0.30%; 95% CI = 0.10% to 0.84%), masses elsewhere (OR = 22; PPV = 0.11%; 95% CI = 0.06% to 0.20%), lymphadenopathy (OR = 10; PPV = 0.09%; 95% CI = 0.06% to 0.13%), symptoms/signs of abnormal movement (OR = 16; PPV = 0.08%; 95% CI = 0.04% to 0.14%), and bruising (OR = 12; PPV = 0·08%; 95% CI = 0.05% to 0.13%). When each of these 12 symptoms was combined singly with at least three consultations in a 3-month period, the probability of cancer was between 11 and 76 in 10 000.

Conclusion

Twelve features of childhood cancers were identified, each of which increased the risk of cancer at least tenfold. These symptoms, particularly when combined with multiple consultations, warrant careful evaluation in general practice.     

Familial risks of congenital heart defect assessed in a population-based epidemiologic study

Congenital heart defects (CHD) represent a heterogeneous group of disorders caused by chromosome abnormalities, mendelian disorders, teratogenic exposures, and unknown etiologic mechanisms. A large group of various isolated defects is presumably multifactorial in origin. Previous studies of familial risks for specific anatomic defects obtained from clinical series may include significant biases and obscured pathogenic relationships. In this population-based study we analyzed all cases of CHD in infants and a control birth cohort in the Baltimore-Washington area. The rates of CHD were defined for first-degree relatives of cases with isolated defects, grouped by a pathogenic classification scheme. Precurrence risks were found to vary among the groups, and risks for flow lesions were higher than previously reported. The sibling precurrence risk for hypoplastic left heart syndrome (13.5%) was not significantly different from that expected for an autosomal recessive mechanism; the risks for different types of ventricular septal defects (VSD) varied among mechanistic groups. The results indicate that the additive multifactorial model does not adequately account for the risks in all forms of isolated CHD of unknown etiology.     

Hormone therapy and cerebrovascular events: a population-based nested case-control study

OBJECTIVE: The relationship between postmenopausal hormone therapy (HT) and cerebrovascular disease has been examined in several epidemiological studies and clinical trials with conflicting results. The authors aimed to evaluate the association between the use of HT and the incidence of first cerebrovascular event. DESIGN: The study cohort comprised 158,031 women 50 to 69 years old registered in the U.K. General Practice Research Database between 1991 and 1997. The authors conducted a nested case-control analysis using all 920 confirmed cases of cerebrovascular events identified during the follow-up (536 of transient ischemic attack [TIA]; 259 of ischemic stroke; 125 of hemorrhagic stroke) and 10,000 controls. RESULTS: The odds ratios of TIA, ischemic stroke, and hemorrhagic stroke among women currently using HT were 1.48 (95% CI, 1.17-1.87), 1.12 (95% CI, 0.78-1.59) and 1.21 (95% CI, 0.76-1.93), respectively, compared to never users. The overall risk estimate for having a cerebrovascular event was 1.34 (95% CI, 1.11-1.61). The risk of TIA was greater (1.96) among women using high doses of estrogen (95% CI, 1.34-2.87). CONCLUSION: Overall, a small increased risk of stroke associated with HT use of comparable magnitude to the one observed in recent clinical trials was found. The increased risk was more apparent for TIA than for stroke and was greater at higher doses.     

Duration of sleep and breast cancer risk in a large population-based case-control study

One important function of sleep may be its contribution to the maintenance of the immune system and regulation of the circadian rhythms by melatonin. Researchers have speculated that disruption of immune functions involving cortisol levels and natural killer cell activity may increase breast cancer risk whereas increased melatonin exposure may protect against breast cancer. We conducted a multistate population-based case-control study of 4,033 women with invasive breast cancer and 5,314 community women without breast cancer in which we inquired about women's sleep habits in the recent past and during adult lifetime. Relative to women who slept 7.0-7.9 h/night, the multivariate odds ratio for developing breast cancer among women who slept an average of 9 h or more per night approximately 2 years prior to interview was 1.13 (95% CI 0.93-1.37). The multivariate-adjusted odds ratio for the continuous term was 1.06 (95% CI 1.01-1.11), suggesting a 6% increase in risk for every additional hour of sleep. Similar patterns were observed for average lifetime adult sleep duration. We found little evidence that sleeping few hours per night was associated with breast cancer risk. The results of this study suggest that increasing sleep duration is modestly associated with an increased breast cancer risk. In contrast, short duration of sleep (<7 h/night) is not substantially associated with increased risk. Further research in this area is warranted.     

A population-based case-control study of isolated primary congenital glaucoma

We studied the possible etiological factors of isolated primary congenital glaucoma (IPCG) using data from the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-2002. The study group consisted of 52 cases with IPCG compared to 52 matched control pairs without any defects, and 22,744 malformed controls with non-ocular defects and 37,837 population controls with no defect. Exposure data and family history were collected (i) prospectively by prenatal logbook and other medical records, (ii) retrospectively through a structured questionnaire completed by mothers, and (iii) from supplementary information obtained by regional nurses visiting the homes of non-respondent mothers. Autosomal recessive inheritance of IPCG was suspected on the basis of sib occurrence and parental consanguinity in 15% of cases. The shorter gestational age (with high proportion of preterm birth), higher birth order, large proportion of births among unmarried women, low socioeconomic status, and high rate of unemployment may be related to Gypsy origin of at least 54% of cases of IPCG. We conclude that the higher incidence of IPCG in the Hungarian Gypsy population is associated with their inbreeding and the possible founder effect of a gene mutation.     

Risk factors for cytogenetically normal holoprosencephaly in California: a population-based case-control study

Holoprosencephaly is a developmental field defect manifested by a spectrum of abnormalities of the forebrain and midface. Approximately 50% of holoprosencephaly cases are associated with a cytogenetic abnormality or a monogenic syndrome. Suggested risk factors for the remaining 50% of cases have been described in case reports, but have not been confirmed in systematically conducted studies. We report the results of a population-based case-control study of holoprosencephaly. Live births, fetal deaths, and terminations with a diagnosis of cytogenetically normal holoprosencephaly were identified by the California Birth Defects Monitoring Program. Telephone interviews were conducted with the mothers of 58 cases and 107 live born, nonmalformed controls. Women were questioned about their health and reproductive histories, family demographics, and exposures occurring during their pregnancies. Among nonsyndromic cases, increased risks were observed for females (OR=1.8, 95% C.I. 0.9-3.9), foreign-born vs. U.S. or Mexico-born women (OR=3.1, 95% C.I. 1.1-8.6), and women with early menarche (OR=2.3, 95% C.I. 0.9-5.7). Maternal periconceptional exposures associated with increased risks for nonsyndromic holoprosencephaly included alcohol consumption (OR=2.0, 95% C.I. 0.9-4.5), cigarette smoking (OR=4.1, 95% C.I. 1.4-12.0), and combined alcohol and smoking (OR=5.4, 95% C.I. 1.4-20.0), insulin-dependent diabetes (OR=10.2, 95% C.I. 1.9-39.4), medications for respiratory illnesses (OR=2.3, 95% C.I. 0.9-6.0), and salicylate-containing medications (OR=2.5, 95% C.I. 0.8-7.9). These findings are consistent with risk factors identified in some previous reports, and identify several new potential risk factors that require confirmation in future studies.     

Clinical features of prostate cancer before diagnosis: a population-based, case-control study

BACKGROUND: Even in areas where screening is available, many prostate cancers are diagnosed after the symptoms begin. However, the risk posed by particular symptoms is largely unknown, especially in unselected populations such as primary care. AIM: To identify and quantify the features of prostate cancer before diagnosis, both individually and in combination. DESIGN OF STUDY: Population-based case-control study. SETTING: All 21 general practices in Exeter, Devon, UK. METHODS: We studied all 217 prostate cancer patients diagnosed between 1998 and 2002, and 1080 male controls, matched by age and general practice. The full medical record for 2 years before diagnosis was coded, using the International Classification of Primary Care. We calculated odds ratios for variables independently associated with cancer, using conditional logistic regression, and calculated the positive predictive values for these, both individually and in combination. RESULTS: Eight features were associated with prostate cancer before diagnosis. Their positive predictive values against a background risk of 0.35% were: urinary retention 3.1% (95% confidence interval [CI] = 1.5 to 6.0); impotence 3.0% (95% CI = 1.7 to 4.9); frequency 2.2% (95% CI = 1.3 to 3.5); hesitancy 3.0% (95% CI = 1.5 to 5.5); nocturia 2.2% (95% CI = 1.2 to 3.6); haematuria 1.0% (95% CI = 0.57 to 1.8); weight loss 0.75% (95% CI = 0.38 to 1.4); abnormal rectal examination, deemed benign 2.8% (95% CI = 1.6 to 4.6); abnormal rectal examination, deemed malignant 12% (95% CI = 5.0 to 37): all P <0.001, except for hesitancy P = 0.032, nocturia P = 0.004 and haematuria P = 0.009. Loss of weight, impotence, frequency and abnormal rectal examination remained associated with cancer after excluding the final 180 days from analysis. CONCLUSION: Most men with prostate cancer present with symptoms. The predictive values for these symptoms will help guide GPs and patients about the value of further investigation.     

Type 2 diabetes is associated with a common mitochondrial variant: evidence from a population-based case-control study

Variants in mitochondrial DNA (mtDNA) could be associated with type 2 diabetes because ATP plays a critical role in the production and release of insulin. Diabetes can be precipitated both by mtDNA mutations and by exposure to mitochondrial poisons. The risk of inheriting diabetes from an affected mother is greater than that from an affected father, but this is not explained by maternally inherited diabetes and/or deafness (MIDD) caused by the 3243G : C mtDNA point mutation, which accounts for less than 0.5% of cases of diabetes. A common mtDNA variant (the 16189 variant) is positively correlated with blood fasting insulin, but there are no definitive studies demonstrating that it is associated with diabetes. We demonstrated a significant association between the 16189 variant and type 2 diabetes in a population-based case-control study in Cambridgeshire, UK (n=932, odds ratio=1.61 (1.0-2.7, P=0.048), which was greatly magnified in individuals with a family history of diabetes from the father's side (odds ratio=infinity; P<0.001).     

E-selectin gene polymorphisms are associated with essential hypertension: a case-control pilot study in a Chinese population

Background  

Genetic variation is thought to contribute to the etiology of hypertension, and E-selectin is a candidate essential hypertension-associated gene. This study thus sought to investigate possible genetic associations between the T1880C, C602A and T1559C polymorphisms of E-selectin and essential hypertension.     

Venous thromboembolism in patients with HIV/AIDS: a case-control study

BACKGROUND: Retrospective cohort studies of HIV-infected patients suggest an incidence of venous thromboembolism (VTE) of 1% to 2%, which is 10 times that expected among people without HIV. We investigated the prevalence of established risk factors for VTE in this population and explored novel risk factors. METHODS: We conducted a case-control study using patients in the Johns Hopkins University AIDS Service cohort. We used conditional logistic regression and paired t tests to test for covariates significantly associated with VTE. RESULTS: We identified 160 patients with VTE diagnosed radiologically or with a clinical course consistent with VTE; 23% of the cases of VTE were diagnosed in hospitalized patients. The incidence of VTE was approximately 0.5% per patient-year. Patients with VTE and control patients did not differ by gender, but black patients were overrepresented among those with VTE (odds ratio [OR]=1.9, 95% confidence interval [CI]: 1.11 to 3.08) and patients with VTE were older than controls (mean: 39 vs. 37 years; P=0.001). Patients with VTE had lower CD4 counts (229 vs. 362 cells/mm; P<0.0001), higher HIV RNA titers (120,254 vs. 71,262 copies/mL; P=0.013), and lower hemoglobin concentrations (11.4 vs. 12.7 g/dL; P<0.0001) preceding the event than those without VTE. The use of highly active antiretroviral therapy was not associated with VTE. In multivariate analyses, independent risks for VTE were age, hospitalization in the past 3 months (OR=13, 95% CI: 6.4 to 27), central venous catheter use in the past 3 months (OR=6.0, 95% CI: 2.3 to 16), and a CD4 count<500 cells/mm (OR=3.0, 95% CI: 1.2 to 7.8). CONCLUSIONS: The incidence of VTE in our cohort is similar to that reported in other cohorts of patients with HIV. Recent hospitalization was the risk factor most strongly associated with VTE.     

Identification of new risk factors for pneumonia: population-based case-control study

Background

Certain conditions are established as risk factors for community-acquired pneumonia. There are a number of other conditions that may also be risk factors, but information on these is limited.

Aim

To determine new independent risk factors for community-acquired pneumonia using a very large primary care database.

Design of study

Nested case-control study.

Setting

Four hundred and forty-three general practices in the UK contributing to the QRESEARCH database.

Method

A total of 17 172 incident cases of all ages diagnosed with pneumonia between 1996 and 2005 were matched with up to five controls by age, sex, general practice, and calendar year. Associations between pneumonia and each established condition and potential risk factors were determined with odds ratios (ORs), using multiple conditional logistic regression analysis adjusted for smoking, socioeconomic status, and use of influenza and pneumococcal vaccines.

Results

The analysis confirmed the higher risk of pneumonia among patients with at least one of the established risk factors; the adjusted OR was 2.29 (95% confidence interval [CI] = 2.20 to 2.39). In addition, patients with the following conditions had a higher risk of pneumonia despite adjustment for known risk factors and confounders: stroke or transient ischaemic attack, rheumatoid arthritis, Parkinson''s disease, cancers, multiple sclerosis, dementia, and osteoporosis. The adjusted OR for pneumonia among patients without an established risk factor but with at least one of the new conditions was 2.44 (95% CI = 2.24 to 2.65).

Conclusion

As well as confirming some established risk factors, this study has determined seven new independent risk factors for community-acquired pneumonia.     

Serum lipids in patients with stroke--a cross-sectional case-control study

BACKGROUND: Vascular disease remains the prime contributor to the pathogenesis of stroke, but dyslipidemia has not been clearly established as a risk factor for stroke the same way it has been for coronary artery disease. There is no case-controlled study on the contribution of serum lipids to stroke in Nigerians. This study aimed at assessing the possibility of serum lipids as risk factor for stroke in Nigerian patients. METHOD: The demography, blood pressure, fasting plasma glucose and fasting serum lipids of 87 consecutive patients with first-ever stroke managed at the University of Benin teaching hospital between January and December 2005 were analyzed and compared with those of age- and sex-matched controls. RESULTS: Eighty-seven stroke patients (55 males and 32 females; mean age 61.25 +/- 14.77 years) were compared with age- and sex-matched controls. Ischemic stroke constituted 64.37%, while the rest had hemorrhagic stroke. There were no significant differences in the serum cholesterol, HDL-C and LDL-C levels of stroke patients and controls (p > 0.05), but the serum triglyceride level was higher among the stroke patients (p < 0.001) with a significant relative risk (RR = 1.77; p < 0.01). CONCLUSION: In this cross-sectional case-control study, there is no significant difference in the serum lipids of Nigerian patients with stroke with the exception of serum triglyceride, which seems to confer significant stroke risk.     

Children at risk of medicinal and non-medicinal poisoning: a population-based case-control study in general practice

Background

Preschool children have a high risk of poisoning. While medicines prescribed by primary care are potential poisoning agents, the risk factors for poisoning from medication are not well described.

Aim

To identify risk factors for medicinal and non-medicinal poisoning in preschool children.

Design and setting

Population-based nested case-control study using The Health Improvement Network primary care database 1988–2004.

Method

Conditional logistic regression was used to identify child, maternal, and social risk factors for medicinal (1316 cases) and non-medicinal poisoning (503 cases), using 17 709 controls matched on general practice.

Results

Poisoning by medicines was independently associated with deprivation (test for trend P<0.001), maternal age (P<0.001), birth order (P<0.001), maternal alcohol misuse (odds ratio [OR] = 5.44, 95% confidence interval [CI] = 1.99 to 14.91), and perinatal depression (OR = 1.54, 95% CI = 1.26 to 1.88). Living in a household with two or more adults lowered the odds of injury compared to single-parent households (OR = 0.85, 95% CI = 0.74 to 0.96) and the odds varied by age, being highest in 2 year olds (OR = 9.61, 95% CI = 7.73 to 11.95). Non-medicinal poisoning was associated with deprivation (P = 0.001), maternal age (P<0.001), and birth order (P<0.001). The odds were raised in 1 year olds (OR = 5.44, 95% CI = 4.07 to 7.26) and 2 year olds (OR = 5.07, 95% CI = 3.73 to 6.90) compared to those aged <1 year.

Conclusion

Primary care data can be used to target interventions to children at risk of poisoning. This is pertinent when prescribing for children/family members, as prescribed medications may become poisoning agents. Prompt identification of maternal depression and alcohol misuse, and delivery of poisoning-prevention interventions at this stage may help prevent poisonings.