Physical exertion (lifting) and retinal detachment among people with myopia.

BACKGROUND: People with myopia (near sightedness) are at increased risk for retinal detachment. We explored other factors that may be associated with retinal detachment within this high-risk group. METHODS: We conducted a case-control study comprising 61 cases with retinal detachment and myopia and 99 hospital controls who also had myopia. Cases were recruited from a general hospital, and controls from ophthalmologic clinics. Participants compiled a questionnaire including details of past and current occupational lifting tasks to explore Valsalva maneuver as a possible risk factor. We devised a cumulative lifting index to distinguish light and heavy lifting. RESULTS: After adjusting for potential confounders, we found strong associations of retinal detachment with eye surgery, eye or head trauma, severe myopia (all known risk factors), and heavy lifting (vs. no lifting, odds ratio = 4.4 [95% confidence interval = 1.5-13]) and high body mass index (>or=25.5 kg/m, 6.8 [1.6-29]). CONCLUSIONS: Heavy occupational lifting and being overweight may be important risk factors for retinal detachment among people with myopia. The role of these risk factors in the etiology of retinal detachment deserves to be explored in more general populations.

Occupational risk factors for renal cell cancer: a case--control study in northern Italy.

Relatively little is known about occupational and other risk factors for renal-cell carcinoma (RCC). Associations between RCC and occupations, exposures and other factors were investigated in a hospital-based case-control study in Bologna (central-northern Italy). Between 1986 and 1994, 324 histologically confirmed RCC cases were diagnosed at Policlinico S. Orsola-Malpighi in patients from the Province of Bologna. Corresponding control subjects admitted to the same hospital with any diagnosis except RCC were matched for sex, age, and residency. We studied the 249 cases and 238 controls for whom detailed information on occupational history, diet, smoking habits, alcohol and drug intake was obtained. At conditional logistic regression, among males (167 matched pairs), significant matched odds ratios (OR) were found, after adjusting for cigarette smoking and alcohol intake, for high body-mass index BMI (third quartile: OR, 4.91; confidence interval [95% CI], 1.56-15.5; last quartile: OR, 4.42; 95% CI, 1.48-13.18), railway workers (OR, 10.14; 95% CI, 1.46-70.17) and asbestos exposure (OR, 7.11; 95% CI, 1.46-34.51); nearly significant OR were found for managers (OR, 3.59; 95% CI, 0.82-15.59) and metal workers (OR, 2.21; 95% CI, 0.99-5.37). Among females (52 pairs), significant OR were found for BMI > 25.4 (OR, 8.46; 95% CI, 1.02-68.0). Railway workers (on or near to trains) may have increased risk of developing RCC, possibly due to asbestos exposure. Studies are required on possible risks encountered by railway (and metal) workers and by managers.