Smoking strongly linked to age-related macular degeneration

One explanation of why we age is the theory of ‘oxidative stress’. This is when the cells of the body are exposed to certain types of molecules called ‘oxidants’. They are unstable molecules and include ‘free radicals’. Oxidants are known to damage the structure of cells which gradually become less able to renew themselves.
We can counteract the effect of oxidants to an extent by ensuring our diet is rich in ‘antioxidants’, usually the vitamins and minerals found in fruit and vegetables.
Cigarette smoke contains 4,500 chemicals, many of which are free radicals. For example, smoke contains arsenic, formaldehyde and ammonia. These chemicals are transported to the delicate tissues of the eye through the bloodstream, where they damage the structure of the cells. Repeatedly exposing delicate retinal cells to these oxidants is effectively fast-forwarding the ageing process.
At the same time as increasing the levels of oxidants in the body, smoking decreases the levels of antioxidants and so reduces the body’s ability to protect itself.
Cigarette smoke also reduces the amount of oxygen reaching the choroid. This is a dense network of tiny blood vessels that supply the retina. Smoking also damages blood vessels themselves, for example the large blood vessels in the heart as well as the tiny ones in the eye. Smoking also increases your overall blood pressure level. High blood pressure is another risk factor for macular degeneration.
Research suggests that the tar in cigarettes triggers the formation of deposits in the retina (drusen) which mark the start of macular degeneration.
Some research suggests that smokers have lower levels of the macular pigments lutein and zeaxanthin. These are antioxidant substances in the macula which are thought to protect it from the damaging effects of sunlight. They are obtained from food, mainly green leafy vegetables like kale and spinach. People with low levels of macular pigment are more likely to develop AMD.-Macular Society
From Wisconsin –
A new report published in Ophthalmology examines the relationship between smoking and age-related macular degeneration. Researchers studied nearly 5,000 individuals participating in a long term trial. Participants had their eyes examined every five years for 20 years.
Results showed that cigarette smoking raised risk of progression of age-related macular degeneration. Having a greater number of pack-years was also associated with raised risk of death.
Source:http://www.insidermedicine.ca/archives/Smoking_strongly_linked_to_agerelated_macular_degeneration_7976.aspx

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