1. Longer index finger is linked to irritability from What Genetic Traits Reveal About Your Health

What Genetic Traits Reveal About Your Health

1. Longer index finger is linked to irritability

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If you’re easily annoyed and lose your temper often, the answer may be in your fingers. Aggression may have biological causes rooted in the length of a person’s ring finger to the index finger, according to a 2012 study. Basically, if the latter is longer, you can be predisposed to flare-ups. All of this may be due to higher prenatal testosterone exposure. However, long index fingers are also linked to lower prostate cancer risk.

2. Bigger thighs may protect against premature death or heart disease

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Most gymgoers — especially women — want to reduce the size of their thighs. But they shouldn’t worry, as a British study says thighs that measure about 24 inches are characteristic of healthy men and women, while thinner thighs were associated with higher risks of heart conditions. The reason may be that a chunkier thigh has more muscle, which results in better regulation of the metabolism and insulin levels.

3. People with naturally red hair are more sensitive to pain

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A study published in the Journal of the American Society of Anesthesiologists says men and women with red hair have increased sensitivity to thermal pain. This means they feel physical discomfort (or agony) a little bit differently than people with other hair colors. Red hair is the phenotype for mutations of the melanocortin 1 receptor, causing pain sensitivity. Research has also shown that redheads are more sensitive to cold, are less responsive to certain anesthetics, and are more likely to be scared of dentists.

4. Ring fingers size in men linked to risk of heart attack

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Like the index finger can determine a bad temperament (see slide 1), the ring finger can show a future risk of a cardiac catastrophe. Studies have found a link between boys whose ring fingers were the same length or shorter than their index fingers and higher risk of a heart attack at an unusually young age – in late 30’s or 40’s. This is due to the fact that men tend to have a relatively longer ring finger because of higher levels of testosterone, which is known to protect against heart problems. Shorter ring fingers mean less testosterone because the genes that are indirectly responsible for the production of testosterone also control the development of the digits.

5. Dark-eyed people are more likely to have cataracts

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People with darker eyes run a higher risk of developing cataracts, clouding of the normally clear lens of the eye. Most cataracts are due to age-related changes in the lens. The first sign of the condition is fogginess over the pupil. A 2000 study published in the American Journal of Ophthalmology says that people with dark eyes have 1.5 to 2.5 times greater risk of cataracts. But whether you have dark eyes or not, it’s always advisable to keep sunglasses or a hat with you if you’re going to be in the sun.

6. Women with small calves are more likely to have a stroke

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A 2009 study has suggested that women whose calves are 13 inches or less, have a greater chance of developing carotid plaque, a condition where plaque builds up inside the arteries. This can lead to a stroke. But regardless of the size of your calves, heart diseases are easy to prevent with a healthy diet and a steady workout plan.

7. People with short arms and legs more likely to develop Alzheimer’s

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The length of people’s arms and legs can reveal more than just basketball skills. A study in the journal of the American Academy of Neurology finds that shorter extremities can be tied to a higher risk of developing Alzheimer's and other forms of dementia. Specifically, a woman's risk dropped 16 percent with every additional inch in knee height and a man’s risk was associated with a 6 percent drop with every increased inch in arm span.

8. Shorter people tend to live longer

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If you’ve ever wished you could be taller, thank your ancestors, because people with shorter body types tend to live longer, according to a 2002 study. They also suffer from chronic illness much later in life than taller people. Researchers observed people living in Greece, China, Japan, Europe and North America for quarter of a century. They found the Greeks, Chinese and Japanese, who were shorter and weighed less, lived longer.

9. Women with light eyes may have a higher tolerance for pain and discomfort

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Two years ago, anesthesiology professor Inna Belfer, MD, PhD, produced evidence suggesting women with light eyes may have a higher tolerance for pain and discomfort. She studied women before and after they had given birth. Those with dark eyes were more anxious and slept worse. They also reacted better when given pain medication, which means they were more sensitive to it.

10. Light-haired people are more prone to AMD

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Older people have vision problems mostly because of age-related macular degeneration (AMD), which is when the center of the retina deteriorates. Studies have shown evidence that having light eyes doubles the risk of developing the condition. More research is needed to confirm a connection, but doctors point out the fact that AMD is more common among Caucasians, who are more likely to have bright eyes.

11. Wide faces and big cheekbones may spell increased aggression

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People with higher levels of testosterone tend to have wider-faces and bigger cheekbones. A study by Dr. Carmen Lefevre of Leeds University has also found them to be more aggressive. The biological reason is that the hormone is linked to higher level of aggressiveness. The “evolutionary” reasoning is that people with wider faces can withstand a punch and are less likely to be hurt.

12. People with dark eyes may be more sensitive to alcohol

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Research collected in 2000 suggests that people with black or brown eyes probably drink less alcohol than those with blue or green eyes. Researchers found that the latter group reported more instances of alcohol abuse. Darker eye pigments are caused by higher levels of melanin, which may cause a greater susceptibility and aversion to alcohol.

13. Redheads are more at risk of developing Parkinson’s

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A study from 2009 that surveyed 131,821 men and women over the course of 16 years concluded those with red hair had the highest risk of developing Parkinson’s, and were almost twice as likely to develop the disease over those with other hair colors.

14. Left-handed people are predisposed to anxiety

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Relax! Feeling anxious or afraid more than others may be due to the fact that your left hand is dominant, a recent study shows. It all has to do with how the brain is wired. Lefties have the right side of the brain, which seems to control fear, as the dominant one.

15. Short legs and long upper body may increase the risk of heart disease

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You have this “condition” when the space between the lowest rib and the top of the hip bone is more than four inches and when the length between the knee and ankle is smaller than the length from the knee to the hip. The chance of coronary heart disease increases 10 percent for every half an inch off your legs length, according to a research published in the Journal of Epidemiology and Community Health.

16. People with thinner faces are less likely to suffer infections

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You may be a skinny person but the extra baby fat on your face may be making you more susceptible to infections. Thinner faces have also been associated with lower risk of depression and anxiety, as physical fitness and mental health are closely related.