Objectives To quantify trends in pediatric computed tomography (CT) use and associated radiation exposure and cancer risk. Design Retrospective observational study. Setting Seven US healthcare systems. Participants CT use was evaluated in children <15 years from 1996-2010, including 4,857,736 child-years of observation. Radiation doses were calculated for 744 CT scans performed between 2001-2011. Outcome Measures Rates of CT use, organ and effective doses, and projected lifetime attributable cancer risks. Results CT use doubled in children <5 years and tripled in children 5-14 between 1996-2005, stabilized until 2007, then declined. Effective doses varied from 0.03-69.2mSv per scan. An effective dose of ≥20mSv was delivered by 14-25% of abdomen/pelvis CTs, 6-14% of spine CTs, and 3-8% of chest CTs. Projected lifetime attributable risks of solid cancer were higher in younger patients and girls, and for abdomen/pelvis and spine CTs. In girls, a radiation-induced solid cancer is projected to result from every 300-390 abdomen/pelvis CTs, 330-480 chest CTs, and 270-800 spine CTs, depending on age. Leukemia risk was highest for head CTs in children <5 at 1.9/10,000. Nationally, 4 million pediatric CTs of the head, abdomen/pelvis, chest, or spine performed each year are projected to cause 4870 future cancers. Reducing the highest 25% of doses to the median might prevent 43% of these cancers. Conclusions Increased use of pediatric CT combined with wide variability in radiation doses has resulted in many children receiving a high-dose examination. Dose-reduction strategies targeted to the highest quartile of doses could dramatically reduce the number of radiation-induced cancers.

Context. Use of diagnostic imaging has increased significantly within fee-for-service models of care.Little is known about patterns of imaging among members of integrated health care systems.Objective. To estimate trends in imaging utilization and associated radiation exposure among members of integrated health care systems.Design, Setting, and Participants. Retrospective analysis of electronic records of members of 6 large integrated health systems from different regions of the United States. Review of medical records allowed direct estimation of radiation exposure from selected tests. Between 1 million and 2 million memberpatients were included each year from 1996 to 2010.

Objective.\p=m-\To assess whether the dietary intake of long-chain n-3 polyunsaturated fatty acids from seafood, assessed both directly and indirectly through a biomarker, is associated with a reduced risk of primary cardiac arrest.Design.\p=m-\Population-based case-control study.Setting.\p=m-\Seattle and suburban King County, Washington. Participants\p=m-\A total of 334 case patients with primary cardiac arrest, aged 25 to 74 years, attended by paramedics during 1988 to 1994 and 493 population-based control cases and controls, matched for age and sex, randomly identified from the community. All cases and controls were free of prior clinical heart disease, major comorbidity, and use of fish oil supplements.Measures of Exposure.\p=m-\Spouses of case patients and control subjects were interviewed to quantify dietary n-3 polyunsaturated fatty acid intake from seafood during the prior month and other clinical characteristics. Blood specimens from 82 cases (collected in the field) and 108 controls were analyzed to determine red blood cell membrane fatty acid composition, a biomarker of dietary n-3 polyunsaturated fatty acid intake.Results.\p=m-\Compared with no dietary intake of eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3), an intake of 5.5 g of n-3 fatty acids per month (the mean of the third quartile and the equivalent of one fatty fish meal per week) was associated with a 50% reduction in the risk of primary cardiac arrest (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.4 to 0.8), after adjustment for potential confounding factors. Compared with a red blood cell membrane n-3 polyunsaturated fatty acid level of 3.3% of total fatty acids (the mean of the lowest quartile), a red blood cell n-3 polyunsaturated fatty acid level of 5.0% of total fatty acids (the mean of the third quartile) was associated with a 70% reduction in the risk of primary cardiac arrest (OR, 0.3; 95% CI, 0.2 to 0.6).Conclusion.\p=m-\Dietary intake of n-3 polyunsaturated fatty acids from seafood is associated with a reduced risk of primary cardiac arrest.

IMPORTANCE Medical imaging increased rapidly from 2000 to 2006, but trends in recent years have not been analyzed. OBJECTIVE To evaluate recent trends in medical imaging. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of patterns of medical imaging between 2000 and 2016 among 16 million to 21 million patients enrolled annually in 7 US integrated and mixed-model insurance health care systems and for individuals receiving care in Ontario, Canada. EXPOSURES Calendar year and country (United States vs Canada). MAIN OUTCOMES AND MEASURES Use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine imaging. Annual and relative imaging rates by imaging modality, country, and age (children [<18 years], adults [18-64 years], and older adults [Ն65 years]). RESULTS Overall, 135 774 532 imaging examinations were included; 5 439 874 (4%) in children, 89 635 312 (66%) in adults, and 40 699 346 (30%) in older adults. Among adults and older adults, imaging rates were significantly higher in 2016 vs 2000 for all imaging modalities other than nuclear medicine. For example, among older adults, CT imaging rates

To reduce the incidence of invasive cervical cancer among women with access to screening and treatment, Pap screening adherence should be increased. In addition, strategies to improve the accuracy of Pap screening could afford earlier detection of cervical cancer.