Editing Radiation hormesis (section)

=== Cancer rates and very high natural background gamma radiation at Kerala, India ===

Kerala's [[monazite]] sand (containing a third of the world's economically recoverable [[List of countries by thorium resources|reserves]] of radioactive [[thorium]]) emits about 8&nbsp;micro[[sievert]]s per hour of gamma radiation, 80&nbsp;times the dose rate equivalent in London, but a decade-long study of 69,985 residents published in Health Physics in 2009 "showed no excess cancer risk from exposure to terrestrial gamma radiation. The excess relative risk of cancer excluding leukemia was estimated to be −0.13 per Gy (95% CI: −0.58, 0.46)", indicating no statistically significant positive or negative relationship between background radiation levels and cancer risk in this sample.<ref name=Nair2009>{{cite journal |doi=10.1097/01.HP.0000327646.54923.11 |title=Background Radiation and Cancer Incidence in Kerala, India – Karanagappally Cohort Study |year=2009 |last1=Nair |first1=Raghu Ram K. |last2=Rajan |first2=Balakrishnan |last3=Akiba |first3=Suminori |last4=Jayalekshmi |first4=P. |last5=Nair |first5=M. Krishnan |last6=Gangadharan |first6=P. |last7=Koga |first7=Taeko |last8=Morishima |first8=Hiroshige |last9=Nakamura |first9=Seiichi |last10=Sugahara |first10=Tsutomu |journal=Health Physics |volume=96 |pages=55–66 |pmid=19066487 |issue=1|s2cid=24657628 |display-authors=8 }}</ref>