By 1981–1982, the annual rate in the United States was high with 92/100,000 among Laotians-Hmong, 82/100,000 among other Laotian ethnic groups, and 59/100,000 among Cambodians.In a 2008 study it was found that over half of SADS deaths could be attributed to inherited heart disease: unexplained premature sudden deaths in family, long QT syndrome, Brugada syndrome, arrhythmogenic right ventricular cardiomyopathy and others.A national SADS study in England, funded by the British Heart Foundation, reported results in a 2007 journal article published in Health. The study surveyed 117 coroners jurisdictions in England. Researchers found that deaths from SADS reported by these coroners occurred "predominantly in young males". There were 500 cases a year in England, which is 8 times more than was previously estimated. Families are more at risk of SADS if they have a genetic cardiac disease. The study recommended that affected families should undergo "specialised cardiological evaluation". Asia
Southeast Asian immigrants, who were mostly fleeing the Vietnam War, most often had this syndrome, marking Southeast Asia as the area containing the most people with this fatal syndrome. There are other Asian populations that were affected, such as Filipinos and Chinese Filipinos, Japanese in Japan, and natives of Guam in the United States and Guam. The immigrants with  this syndrome were about 33 years old and seemingly healthy, and all but one of the Laotian Hmong refugees were men. The condition appears to primarily affect young Hmong men from Laos (median age 33) and Northeastern Thailand (where the population is mainly of Laotian descent).
The mechanism of action of timolol is probably the reduction of the formation of aqueous humor in the ciliary body in the eye. It was the first beta blocker approved for topical use in treatment of glaucoma in the United States (1978). When used by itself, it depresses intraocular pressure (IOP) 18–34% below baseline within first few treatments. However, there are short-term escape and long-term drift effects in some people. That is, tolerance develops. It may reduce the extent of the diurnal IOP curve up to 50%. The IOP is higher during sleep. Efficacy of timolol in lowering IOP during the sleep period may be limited. It is a 5–10× more potent β-blocker than propranolol. Timolol is light-sensitive; it is usually preserved with 0.01% benzalkonium chloride (BAC), but also comes BAC-free. It can also be used in combination with pilocarpine, carbonic anhydrase inhibitors or prostaglandin analogs.A Cochrane review compared the effect of timolol versus brimonidine in slowing the progression of open angle glaucoma in adults but found insufficient evidence to come to conclusions. On the skin
In its gel form it is used on the skin to treat infantile hemangiomas. Contraindications
The medication should not be taken by individuals with:
An allergy to timolol or any other beta-blockers
Asthma or severe chronic obstructive bronchitis
A slow heart rate (bradycardia), or a heart block
Heart failure

Side effects
The most serious possible side effects include cardiac arrhythmias and severe bronchospasms.