Breaking the matching in nested case-control data offered several advantages for risk estimation.

Objective: To demonstrate the advantage of using weighted Cox regression to analyze nested case-control data in overcoming limitations encountered with traditional conditional logistic regression.

Study Design And Setting: We analyzed data from 1,051 women who were sampled in a case-control study of lung cancer nested within a cohort of breast cancer patients. We investigated how lung cancer risk is associated with radiation therapy and modified by smoking, with both conditional logistic regression and weighted Cox regression models.

Common genetic variations in cell cycle and DNA repair pathways associated with pediatric brain tumor susceptibility.

Knowledge on the role of genetic polymorphisms in the etiology of pediatric brain tumors (PBTs) is limited. Therefore, we investigated the association between single nucleotide polymorphisms (SNPs), identified by candidate gene-association studies on adult brain tumors, and PBT risk.The study is based on the largest series of PBT cases to date.

CCDC26, CDKN2BAS, RTEL1 and TERT Polymorphisms in pediatric brain tumor susceptibility.

The role of genetic polymorphisms in pediatric brain tumor (PBT) etiology is poorly understood. We hypothesized that single nucleotide polymorphisms (SNPs) identified in genome-wide association studies (GWAS) on adult glioma would also be associated with PBT risk. The study is based on the Cefalo study, a population-based multicenter case-control study.

Validation of self-reported start year of mobile phone use in a Swedish case-control study on radiofrequency fields and acoustic neuroma risk.

The possible effect of radiofrequency exposure from mobile phones on tumor risk has been studied since the late 1990s. Yet, empirical information about recall of the start of mobile phone use among adult cases and controls has never been reported. Limited knowledge about recall errors hampers interpretations of the epidemiological evidence.

Loud noise exposure and acoustic neuroma.

The results from studies of loud noise exposure and acoustic neuroma are conflicting. A population-based case-control study of 451 acoustic neuroma patients and 710 age-, sex-, and region-matched controls was conducted in Sweden between 2002 and 2007. Occupational exposure was based on historical measurements of occupational noise (321 job titles summarized by a job exposure matrix) and compared with self-reported occupational noise exposure.

Long-term mobile phone use and acoustic neuroma risk.

Background: There is concern about potential effects of radiofrequency fields generated by mobile phones on cancer risk. Most previous studies have found no association between mobile phone use and acoustic neuroma, although information about long-term use is limited.

Methods: We conducted a population-based, nation-wide, case-control study of acoustic neuroma in Sweden.

Brain tumors in children and adolescents and exposure to animals and farm life: a multicenter case-control study (CEFALO).

Objectives: The etiology of brain tumors in children and adolescents is largely unknown, and very few environmental risk factors have been identified. The aim of this study was to examine the relationship between pre- or postnatal animal contacts or farm exposures and the risk of childhood brain tumors (CBTs), since infectious agents may pose a risk factor and a proposed mechanism is transferral of infectious agents from animals to humans.

Methods: The case-control study conducted in Denmark, Norway, Sweden, and Switzerland included brain tumor cases diagnosed from 2004 to 2008 aged 7-19 years at diagnosis.

Role of tobacco use in the etiology of acoustic neuroma.

Two previous studies suggest that cigarette smoking reduces acoustic neuroma risk; however, an association between use of snuff tobacco and acoustic neuroma has not been investigated previously. The authors conducted a case-control study in Sweden from 2002 to 2007, in which 451 cases and 710 population-based controls completed questionnaires. Cases and controls were matched on gender, region, and age within 5 years.

Predictors and overestimation of recalled mobile phone use among children and adolescents.

A growing body of literature addresses possible health effects of mobile phone use in children and adolescents by relying on the study participants' retrospective reconstruction of mobile phone use. In this study, we used data from the international case-control study CEFALO to compare self-reported with objectively operator-recorded mobile phone use. The aim of the study was to assess predictors of level of mobile phone use as well as factors that are associated with overestimating own mobile phone use.

Mobile phone use and brain tumors in children and adolescents: a multicenter case-control study.

Background: It has been hypothesized that children and adolescents might be more vulnerable to possible health effects from mobile phone exposure than adults. We investigated whether mobile phone use is associated with brain tumor risk among children and adolescents.

Methods: CEFALO is a multicenter case-control study conducted in Denmark, Sweden, Norway, and Switzerland that includes all children and adolescents aged 7-19 years who were diagnosed with a brain tumor between 2004 and 2008.

Impact of random and systematic recall errors and selection bias in case--control studies on mobile phone use and brain tumors in adolescents (CEFALO study).

Whether the use of mobile phones is a risk factor for brain tumors in adolescents is currently being studied. Case--control studies investigating this possible relationship are prone to recall error and selection bias. We assessed the potential impact of random and systematic recall error and selection bias on odds ratios (ORs) by performing simulations based on real data from an ongoing case--control study of mobile phones and brain tumor risk in children and adolescents (CEFALO study).

Occupational exposures and risk of acoustic neuroma.

Objectives: Acoustic neuroma is a benign tumour accounting for approximately 6-10% of all intracranial tumours and occurs mainly in patients aged ≥50 years. Our aim was to investigate a wide range of occupational exposures, individual occupational titles and socioeconomic status (SES) as potential risk factors for acoustic neuroma.

Methods: We conducted a population-based case-control study of 793 acoustic neuroma cases identified through the Swedish Cancer Registry and 101,762 randomly selected controls.

Validation of smoking history in cancer patients.

Objective: The aim of the study was to investigate the agreement between patient records and the information reported from relatives, and how the relationship and time since patient's death affected the response rate and the quality of the data.

Methods: A questionnaire regarding smoking history was sent to next-of-kin of 270 deceased women diagnosed with breast cancer during 1958-2000 in the Stockholm County. Agreement between the reports of next-of-kin and patient records was calculated using a kappa statistics, along with its 95% confidence interval.

Ionizing radiation and tobacco use increases the risk of a subsequent lung carcinoma in women with breast cancer: case-only design.

Purpose: To analyze the risk of lung cancer in women treated with radiotherapy for breast cancer. We accessed the lung dose in relation to different radiotherapy techniques, provided the excess relative risk (ERR) estimate for radiation-associated lung cancer, and evaluated the influence of tobacco use.

Patients And Methods: The Swedish Cancer Registry was used to identify 182 women diagnosed with breast and subsequent lung cancers in Stockholm County during 1958 to 2000.