Stretch marks might have a genetic basis, new research suggests.
The research, published as a letter to the editor in the Journal of Investigative Dermatology, shows that there are four genetic markers that seem to be linked with stretch marks. The study was conducted by scientists from the personal genetics company 23andMe.
The study involved genome-wide association analysis of 33,930 customers of 23andMe. All the study participants were of European descent; 13,930 people had stretch marks, while 20,862 did not.
Researchers further looked at gene variants in 4,967 women who reported the severity of their stretch marks experienced during pregnancy.
Through this analysis, researchers were able to identify four genetic regions tied to stretch marks. Specifically, they found that one particular DNA sequence variation linked with the pregnancy-related stretch marks was located closely to the elastin gene; elastin is "the major component of elastic fibers, which provide reversible extensibility to connective tissue," the researchers wrote in the study.
Stretch marks are extremely common, with anywhere from 50 to 80 percent of all people experiencing them, researchers noted. Also called "striae," they often appear as colored streaks in the skin, most commonly around the thighs, butt, arms and abdomen, the Mayo Clinic reported. Pregnant women may also have an increased risk of stretch marks due to their growing bellies. Weight gain, certain conditions and use of some medications (like corticosteroid creams) are known causes of stretch marks.
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Not Using Sunscreen
The Skin Cancer Foundation reports that 90 percent of non-melanoma skin cancers in the U.S. are linked to sun exposure, and yet many of us still are not protecting ourselves. In fact, 49 percent of men and 29 percent of women say they <a href="http://www.prnewswire.com/news-releases/new-survey-reveals-gender-divide-surrounding-skin-cancer-awareness-and-prevention-159696285.html" target="_hplink">have not used sunscreen in the past 12 months</a>, according to a recent survey from The Skin Cancer Foundation. Part of the reason why is that there's simple confusion as to what works and for how long. Only 32 percent of men said they considered themselves extremely or very knowledgeable about how to get adequate sun protection, according to the survey. But anything is better than nothing. "Honestly, <a href="http://www.huffingtonpost.com/2012/05/26/sunscreen-guide-2012_n_1545553.html#slide=1025367" target="_hplink">the best sunscreen is whatever the patient uses</a>," Dr. Bobby Buka, a dermatologist in private practice in New York City, told HuffPost in May. "I'm not going to fight the battle about formulation."
Applying Sunscreen Incorrectly
Even among sunscreen loyalists, there's confusion as to how <em>much</em> sunscreen you really need and how often you should reapply. More than 60 percent of men said they believed one application would protect them for at least four hours, according to the same Skin Cancer Foundation survey. In reality, most sunscreens should be reapplied every two hours, and more frequently if you're swimming or sweating. During each application, make sure to use enough sunscreen to "generously coat" any skin that won't be covered by clothes, the American Academy of Dermatology recommends. Generally, that will be <a href="http://www.aad.org/media-resources/stats-and-facts/prevention-and-care/sunscreens" target="_hplink">about an ounce of sunscreen</a>, or enough to fill a shot glass, although you may need more depending on body size. One study found that <a href="http://www.ncbi.nlm.nih.gov/pubmed/12374537" target="_hplink">most people use less than half that amount</a>. <em>Flickr photo by <a href="http://www.flickr.com/photos/helloturkeytoe/5853425982/" target="_hplink">Hello Turkey Toe</a></em>
Not Wearing Sunglasses
If you're not protecting your peepers when you're in the sun (and <a href="http://www.thevisioncouncil.org/news/news_item.cfm?OID=16722" target="_hplink">27 percent of U.S. adults say they never do</a>, according to a report from trade group The Vision Council), you're exposing yourself to a greater risk of cataracts, macular degeneration and skin cancer on the eyelids, which accounts for <a href="http://www.redbookmag.com/beauty-fashion/tips-advice/skin-sun-care-3" target="_hplink">up to 10 percent of all skin cancers</a>, <em>Redbook</em> reported. It's also important to throw on the right pair. Those cheap ones you picked up may not meet recommendations for UV ray protection. Look for a pair that blocks at least <a href="http://news.menshealth.com/sunglasses/2012/05/27/" target="_hplink">99 percent of UVA and UVB rays</a>, <em>Men's Health</em> reported, although that can be tricky because stores may label products incorrectly. Your best bet is to bring your sunglasses to an eye doctor, who can scan the lenses to measure how much protection they offer. Wearing sunglasses can also <a href="http://abcnews.go.com/Health/WellnessResource/story?id=7709444" target="_hplink">help minimize wrinkles and fine lines</a> caused by squinting. <em>Flickr photo by <a href="http://www.flickr.com/photos/dichohecho/3301167394/" target="_hplink">dichohecho</a></em>
Taking A Dip Right After Shaving
If you want to look smooth before lounging poolside, take note that going in the water right after shaving, waxing or undergoing laser hair removal can cause <a href="http://www.glamour.com/beauty/2009/05/summer-beauty-mistakes-and-how-to-avoid-them#slide=5" target="_hplink">irritation to that extra-sensitive skin</a>, according to Glamour.com. Try to finish up the beauty routine at least a few hours before it's time to make a splash. <em>Flickr photo by <a href="http://www.flickr.com/photos/xlordashx/2618532915/" target="_hplink">xlordashx</a></em>
Not Staying Hydrated
Feeling parched from the summer heat? Your skin may be too! <a href="http://www.dailyglow.com/photo-gallery/fix-your-summer-beauty-mistakes#/slide-3" target="_hplink">Sun exposure saps moisture from skin</a>, which can leave you looking flaky and scaly, Daily Glow explains. Richer lotions and moisturizers are a good start, but part of the problem is you're likely not moisturizing from the inside out. <a href="http://www.huffingtonpost.com/2012/05/07/drinking-water-week-more-water_n_1474999.html" target="_hplink">Drinking more water</a> can help, as can other hydrating sips, like <a href="http://www.huffingtonpost.com/2012/02/09/coconut-water-exercise_n_1250810.html" target="_hplink">coconut water,</a> and eating <a href="http://www.huffingtonpost.com/2012/02/24/6-hydrating-foods_n_1297196.html" target="_hplink">foods with high water content</a>, like watermelon and cucumbers. <em>Flickr photo by <a href="http://www.flickr.com/photos/rachelkramerbusseldotcom/5422057584/" target="_hplink">rachelkramerbussel.com</a></em>
Neglecting Your Feet
Spending a lot of time in flip-flops can cause <a href="http://www.huffingtonpost.com/2012/05/25/healthy-feet_n_1544609.html#slide=1020851" target="_hplink">the skin around the heel to crack</a>, HuffPost reported in May. Moisturizing daily can help, as can a weekly date with the pumice stone. If you're not too hot, Glamour.com recommends <a href="http://www.glamour.com/beauty/2009/05/summer-beauty-mistakes-and-how-to-avoid-them#slide=4" target="_hplink">sleeping in socks</a>. The fabric can help your <a href="http://www.glamour.com/beauty/2009/05/summer-beauty-mistakes-and-how-to-avoid-them#slide=2" target="_hplink">moisturizer soak in</a>.
Scratching Bug Bites
We know that itch can feel like torture, but scratching itchy summer bug bites is a bad idea, Dr. Neal B. Schultz, a board-certified dermatologist in practice in New York City, told HuffPost in June. You're likely to break the skin more by scratching, which can expose the bite to infection. And scratching will only make bites <em>more</em> inflamed, he said, leading to greater itchiness and pain. Instead, <a href="http://www.huffingtonpost.com/2012/06/20/natural-mosquito-bite-treatment_n_1610186.html" target="_hplink">try a natural treatment</a>, like ice, vinegar, witch hazel and more.