ID Number		313
Study Type		Epidemiology
Model		INTERPHONE - Israeli National site 900, 1800 MHz (NMT, GSM, W-CDMA) mobile phone use and correlation with brain, acoustic nerve, parotid gland tumors
Details		Cases of benign (n = 402) and malignant (n = 58) parotid gland tumors identified between 2001 to 2003 were evaluated for correlations with mobile phone use as part of the INTERPHONE study. Over the entire group, no correlation was observed (OR = 0.87; 95% CI 0.68-1.13). However when heavy users (more than 22 hours per month) and users in rural areas were evaluated, consistently elevated risks were observed. When ipsilateral use in "heavy users" was evaluated, statistically significant correlations were observed with highest cummulative number of calls(OR = 1.58, 95% CI 1.11-2.24) and highest cumulative call time (OR = 1.49, 95% CI 1.05-2.13). Similar correlations in the highest exposure groups were observed with ipsilateral use without hands free kits (OR = 1.49; 95% CI 1.05 - 2.13). These observations were reported to have a positive dose response relationship. The authors suggest an association between mobile phone use and parotid gland tumors. Overall study findings: OR = 0.87; 95% CI 0.68-1.13 - salivary overall, OR = 1.58; 95% CI 1.11- 2.24 - ipsilateral + highest number of calls, OR = 1.49; 95% CI 1.05- 2.13 - ipsilateral + highest call time.
Findings		Effects
Status		Completed With Publication
Principal Investigator		Chaim Sheba Medical Center, Israel
Funding Agency		EU, INTERPHONE (IARC) coordinated studies, MMF, GSM Association
Country		ISRAEL
References		Sadetzki, S et al. Am J Epidemiol, (2008) 167:457-467
Comments		The authors admit to presenting the study as a "cellular telephone study", so the findings of Vrijheid et al (2008) of possible over-estimation bias are quite likely. The initial evaluation of all users showed no correlation with mobile phone use. Only after "heavy users" were identified (n = ~287 cases of the original 402) was there a correlation with ipsilateral use. Importantly, in obtaining this "heavy user" set, the matching with controls was lost, opening the study to bias. The definition of "heavy users" was not clearly provided, other than "Among our controls, the 75th percentiles for cumulative call time and cumulative number of calls were 1,348 hours and 26,100 calls, respectively, compared with 450 hours and 7,350 calls in a Swedish and Danish report (14) and 534 hours and 8,000 calls in a pooled analysis of north European INTERPHONE study countries (12)". Also, the reason so many parotid gland tumors were obtained in this study is that the authors went beyond the tumor registries (malignant tumors) and obtained additional benign tumors for analysis. It is not clear the contribution of benign tumors to the "regular user" group, but it was about 80-90% of the total tumors (n = 402). In assessing individual expsoure, the users (especially the cases) may have been informed of the nature of the study, and thus over-estimation bias may have existed. UICC acts as a firewall for funding by MMF and GSMA - see http://www.iarc.fr/pageroot/UNITS/RCA4.html for details)