F.Y.EYE

Trial confirms regular sunscreen use reduces dcancer risk

It is commonly accepted that sunscreen use reduces therisk of skin cancer, but there had been no randomizedstudies to prove this until recently. Australian researcherspublished the first randomized study looking at this ques-tion. The study looked at 1621 residents of Nambour, atown in the Queensland district of Australia, which is pur-ported to have the highest rate of skin cancer in the world.The participants were randomly selected and randomlyassigned to either daily use of sunscreen with an SPF of 15on their head and arms or discretionary sunscreen applica-tion to their head and arms (meaning that the participantsdecided when to apply sunscreen, which for some meantnever). The study participants were enrolled in 1992 andthe study ran until 1996. During the study, 75% of thedaily use group complied with the directions, and in thediscretionary group 38% never used sunscreen, and 35%used it once or twice a week. For 10 years after the studywas completed the participants were observed with ques-tionnaires and screening of the cancer registry and pathol-ogy reports to determine the rate of melanoma. At the10-year mark, 11 participants in the daily sunscreen grouphad developed primary melanoma, compared to 22 in thediscretionary sunscreen group (hazard ratio [HR] � 0.5;95% confidence interval [CI] � 0.24–1.02; p � 0.51).When the results were analyzed for invasive melanoma, thereduction was substantial compared to preinvasive mela-noma. For invasive melanoma, there were 3 in the sun-screen group compared to 11 in the discretionary group(HR � 0.27; 95% CI � 0.08–0.97; p � 0.045). Forpreinvasive melanoma there were 8 versus 11 cases (HR �0.73; 95% CI � 0.29–1.81; p � 0.49). Authors of anaccompanying editorial conclude that the results shouldresolve any question regarding the efficacy of regular sun-screen use for melanoma prevention.Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma afterregular sunscreen use: randomized trial follow-up. J Clin Oncol. 2011;29:257-63.

Allergic reactions during anaesthesia higher thanpreviously thought

French researchers found that the rate of allergic reac-tions during anaesthesia is potentially higher than previ-ously reported. Previous estimates from studies in the1990s estimated the rate of allergic reactions during anaes-

thesia at 100 for every 1.3 million anaesthetic procedures.

376 CAN J OPHTHALMOL—VOL. 46, NO. 4, AUGUST 2011

Reviewing data from 2 national databases, including thepharmacovigilence system, researchers looked at the num-ber of patients experiencing adverse events from anaesthet-ics between January 1997 and December 2004. Duringthis time period, data for 2516 adverse allergic reactionswas obtained with 72% being IgE mediated (1816 cases),with neuromuscular blocking agents being the most com-mon cause (58.08%), followed by latex (19.65%), andthen antibiotics (12.85%). The rate for women was higherthan men, with a median annual incidence of 154.9 permillion procedures compared to 55.4 per million proce-dures for men. Overall, the rate of allergic reactions was100 for every 1 million anaesthetic procedures, comparedto the previously published rates of 100 for every 1.3 mil-lion.Mertes PM, Alla F, Tréchot P, et al. Anaphylaxis during anesthesia in France:an 8-year national survey. J Allergy Clin Immunol. 2011 Apr 15. [Epub aheadof printt].

Lithium in drinking water may reduced suicide ratesLithium naturally occurs in municipal drinking water,

and Austrian researchers looked at whether there was anyassociation between suicide rates and levels of lithium indrinking water. The researchers looked at lithium levelsnationwide, using 6460 measurements of lithium in thelocal drinking water across the country. They comparedthese measurements to the suicide rate across 99 districts ofAustria. The authors used a multivariate analysis to adjustfor various socioeconomic variables (such as availability ofmental health services and the proportion of Roman Cath-olics) known to affect suicide rates, Comparing the 10regions with the highest lithium concentration to the 10with the lowest lithium levels, the rate of suicide was 11 per100 000 versus 16 per 100 000. The overall suicide rateand suicide mortality rate were inversely associated withlithium levels (p � 0.000073 and p � 0.000030). Theauthors conclude that the results suggest higher lithiumlevels is protective against suicide but that given the natureof the study it cannot be concluded that higher lithiumlevels causes a reduction in the rate of suicide.Kapusta ND, Mossaheb N, Etzersdorfer E, et al. Lithium in drinking waterand suicide mortality. Br J Psychiatry. 2011;198:346-50.

F.Y.Eye presents summaries of publications and news stories ofinterest to ophthalmologists. If you have any suggestions orcontributions, please send them to Ian McIlraith, MD, at

imcilrai@uwo.ca.