Limits...
Radiation exposure and circulatory disease risk: Hiroshima and Nagasaki atomic bomb survivor data, 1950-2003.

Shimizu Y, Kodama K, Nishi N, Kasagi F, Suyama A, Soda M, Grant EJ, Sugiyama H, Sakata R, Moriwaki H, Hayashi M, Konda M, Shore RE - BMJ (2010)

Bottom Line: For heart disease, the estimated excess relative risk per gray was 14% (6% to 23%, P<0.001); a linear model provided the best fit, suggesting excess risk even at lower doses.However, the dose-response effect over the restricted dose range of 0 to 0.5 Gy was not significant.Doses above 0.5 Gy are associated with an elevated risk of both stroke and heart disease, but the degree of risk at lower doses is unclear.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology, Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan. shimizu@rerf.or.jp

ABSTRACT

Objective: To investigate the degree to which ionising radiation confers risk of mortality from heart disease and stroke.

Design: Prospective cohort study with more than 50 years of follow-up.

Setting: Atomic bomb survivors in Hiroshima and Nagasaki, Japan.

Participants: 86 611 Life Span Study cohort members with individually estimated radiation doses from 0 to >3 Gy (86% received <0.2 Gy).

Main outcome measures: Mortality from stroke or heart disease as the underlying cause of death and dose-response relations with atomic bomb radiation.

Results: About 9600 participants died of stroke and 8400 died of heart disease between 1950 and 2003. For stroke, the estimated excess relative risk per gray was 9% (95% confidence interval 1% to 17%, P=0.02) on the basis of a linear dose-response model, but an indication of possible upward curvature suggested relatively little risk at low doses. For heart disease, the estimated excess relative risk per gray was 14% (6% to 23%, P<0.001); a linear model provided the best fit, suggesting excess risk even at lower doses. However, the dose-response effect over the restricted dose range of 0 to 0.5 Gy was not significant. Prospective data on smoking, alcohol intake, education, occupation, obesity, and diabetes had almost no impact on the radiation risk estimates for either stroke or heart disease, and misdiagnosis of cancers as circulatory diseases could not account for the associations seen.

Conclusion: Doses above 0.5 Gy are associated with an elevated risk of both stroke and heart disease, but the degree of risk at lower doses is unclear. Stroke and heart disease together account for about one third as many radiation associated excess deaths as do cancers among atomic bomb survivors.

Show MeSH

Related in: MedlinePlus

Fig 2 Radiation dose-response relation (excess relative risk) for death from heart disease, showing linear and linear-quadratic functions. Shaded area is 95% confidence region for fitted linear line. Vertical lines are 95% confidence intervals for specific dose category risks. Point estimates of risk for each dose category are indicated by circles
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC2806940&req=5

fig2: Fig 2 Radiation dose-response relation (excess relative risk) for death from heart disease, showing linear and linear-quadratic functions. Shaded area is 95% confidence region for fitted linear line. Vertical lines are 95% confidence intervals for specific dose category risks. Point estimates of risk for each dose category are indicated by circles

Mentions: The excess relative risk per Gy for all heart disease based on the linear model in the full dose range was 14% (6% to 23%, p<0.001) (table 2). Figure 2 shows the results for the linear and linear-quadratic models. The test for non-linearity based on a comparison of linear and linear-quadratic dose-response models was not statistically significant (P>0.5). A pure linear model fitted the data nominally better than did a pure dose-squared model (difference in Akaike information criterion statistics of 2.47). The excess relative risks per Gy for heart disease over restricted dose ranges were similar to that for the full dose range. Specifically, the excess relative risk per Gy based on the linear model for the dose ranges under 2, 1, and 0.5 Gy were 14% (4% to 25%), 18% (3% to 33%), and 20% (−5% to 45%). In figure 2, the slope over the lower part of the dose range was almost identical to the one for the entire dose range. The best estimate of a threshold dose was 0 Gy, with an upper 95% confidence limit of about 0.5 Gy. We found no significant modification of effect by sex, age at exposure, or age at risk (web table A).


Radiation exposure and circulatory disease risk: Hiroshima and Nagasaki atomic bomb survivor data, 1950-2003.

Shimizu Y, Kodama K, Nishi N, Kasagi F, Suyama A, Soda M, Grant EJ, Sugiyama H, Sakata R, Moriwaki H, Hayashi M, Konda M, Shore RE - BMJ (2010)

Fig 2 Radiation dose-response relation (excess relative risk) for death from heart disease, showing linear and linear-quadratic functions. Shaded area is 95% confidence region for fitted linear line. Vertical lines are 95% confidence intervals for specific dose category risks. Point estimates of risk for each dose category are indicated by circles
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2806940&req=5

fig2: Fig 2 Radiation dose-response relation (excess relative risk) for death from heart disease, showing linear and linear-quadratic functions. Shaded area is 95% confidence region for fitted linear line. Vertical lines are 95% confidence intervals for specific dose category risks. Point estimates of risk for each dose category are indicated by circles
Mentions: The excess relative risk per Gy for all heart disease based on the linear model in the full dose range was 14% (6% to 23%, p<0.001) (table 2). Figure 2 shows the results for the linear and linear-quadratic models. The test for non-linearity based on a comparison of linear and linear-quadratic dose-response models was not statistically significant (P>0.5). A pure linear model fitted the data nominally better than did a pure dose-squared model (difference in Akaike information criterion statistics of 2.47). The excess relative risks per Gy for heart disease over restricted dose ranges were similar to that for the full dose range. Specifically, the excess relative risk per Gy based on the linear model for the dose ranges under 2, 1, and 0.5 Gy were 14% (4% to 25%), 18% (3% to 33%), and 20% (−5% to 45%). In figure 2, the slope over the lower part of the dose range was almost identical to the one for the entire dose range. The best estimate of a threshold dose was 0 Gy, with an upper 95% confidence limit of about 0.5 Gy. We found no significant modification of effect by sex, age at exposure, or age at risk (web table A).

Bottom Line: For heart disease, the estimated excess relative risk per gray was 14% (6% to 23%, P<0.001); a linear model provided the best fit, suggesting excess risk even at lower doses.However, the dose-response effect over the restricted dose range of 0 to 0.5 Gy was not significant.Doses above 0.5 Gy are associated with an elevated risk of both stroke and heart disease, but the degree of risk at lower doses is unclear.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology, Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan. shimizu@rerf.or.jp

ABSTRACT

Objective: To investigate the degree to which ionising radiation confers risk of mortality from heart disease and stroke.

Design: Prospective cohort study with more than 50 years of follow-up.

Setting: Atomic bomb survivors in Hiroshima and Nagasaki, Japan.

Participants: 86 611 Life Span Study cohort members with individually estimated radiation doses from 0 to >3 Gy (86% received <0.2 Gy).

Main outcome measures: Mortality from stroke or heart disease as the underlying cause of death and dose-response relations with atomic bomb radiation.

Results: About 9600 participants died of stroke and 8400 died of heart disease between 1950 and 2003. For stroke, the estimated excess relative risk per gray was 9% (95% confidence interval 1% to 17%, P=0.02) on the basis of a linear dose-response model, but an indication of possible upward curvature suggested relatively little risk at low doses. For heart disease, the estimated excess relative risk per gray was 14% (6% to 23%, P<0.001); a linear model provided the best fit, suggesting excess risk even at lower doses. However, the dose-response effect over the restricted dose range of 0 to 0.5 Gy was not significant. Prospective data on smoking, alcohol intake, education, occupation, obesity, and diabetes had almost no impact on the radiation risk estimates for either stroke or heart disease, and misdiagnosis of cancers as circulatory diseases could not account for the associations seen.

Conclusion: Doses above 0.5 Gy are associated with an elevated risk of both stroke and heart disease, but the degree of risk at lower doses is unclear. Stroke and heart disease together account for about one third as many radiation associated excess deaths as do cancers among atomic bomb survivors.

Show MeSH
Related in: MedlinePlus