Patients with arthritic knees can add hip-strengthening exercises to their workout to improve the ability to walk and maybe reduce pain, according to a research review.
Based on pooled data from eight clinical trials with a total of 340 patients, the study team concludes in the British Journal of Sports Medicine that hip strengthening exercises involving weights or elastic bands would help the most.
“Despite knowing that exercise is beneficial, what type of exercise should be included in a thorough exercise program remains largely unknown,” said lead author Andrew Hislop of the University of Queensland in Brisbane, Australia.
Most international guidelines recommend exercise in the conservative management of knee osteoarthritis, a bone and cartilage disease that affects one in four people over age 55. However, many doctors don’t follow up on this advice with patients or refer them to the proper physiotherapist for an additional appointment, Hislop noted.
“With a growing population and increasing number of lower limb injuries, there is going to be an ever increasing burden on the health system to manage knee osteoarthritis,” he told Reuters Health by email.
Hislop and colleagues conducted a systematic review and meta-analysis of randomized controlled trials that investigated the effect of adding hip-strengthening exercises to a regimen often prescribed to strengthen the quadriceps muscles at the front of the thigh for people with knee arthritis.
The researchers looked at whether aspects of knee and walking function improved, as well as whether pain and quality of life were affected by the added hip-strengthening routine.
They also evaluated three types of hip exercises to see which had the greatest effect: resistance weight-lifting, functional neuromuscular exercises such as single-leg squats or stepping, and so-called multimodal exercise that combined these two.
Overall, adding hip-strengthening significantly improved walking function, though it did not have a statistically meaningful effect on pain, stair function or the ability to stand from a sitting position.
When researchers looked at individual types of hip exercise, however, they found that resistance exercises in particular were more effective than functional neuromuscular exercises for improving pain and functioning. Multimodal exercise had no added effect.
“Strengthening the hip muscles, particularly the hip abductors, might improve pelvic drop and trunk control, lightening the load on the knee,” Hislop said.
“Many health professionals are concerned only with the site affected by the disease, forgetting the regional consequences of the disease” at the hip or beyond, said Dr. Jamil Natour, chief of rheumatology at the Federal University of Sao Paulo in Brazil, who wasn’t involved in the study.
“We should verify that the ‘normal’ hip of a patient with knee osteoarthritis is evaluated and possibly rehabilitated,” he told Reuters Health by email.
Researchers also want to understand exactly how exercise influences knee osteoarthritis pain. The effect be physical, but could also stem from other factors such as a general improvement in wellbeing, attention from a healthcare professional or a placebo effect.
“Over the last decade or so, many researchers have looked for the optimal exercise program, but unfortunately, without luck,” said Marius Henriksen, head of the Physiotherapy and Biomechanics Research unit at Copenhagen University Hospital in Frederiksberg, Denmark, who wasn’t involved with the study.
“To me, that suggests that the exercise that is effective is the exercise that is being done,” he told Reuters Health by email. “Go out there and exercise and be physically active, and do something that you find fun and meaningful.”
Has a high-fat meal ever left you feeling bloated and sluggish? It turns out that a heavier fat diet may keep the many bacteria that live in your digestive system from doing their best, too.
New research found that when people boosted their fat intake to 40 percent of their daily diet for six months, the number of "good" gut bacteria decreased while "unhelpful" bacteria amounts increased.
"The [study] result showed that a high-fat diet is linked to unfavorable changes in the type and numbers of gut bacteria -- collectively known as the microbiome," said the study's senior author, Duo Li. He is chief professor of nutrition at the Institute of Nutrition and Health at Qingdao University in Qingdao, China.
In addition to changing the make-up of the microbiome, the study authors also noted an increase in inflammatory triggers in the body. These changes may contribute to the development of metabolic disorders, such as diabetes and heart disease, the researchers noted.
Nutritionist Samantha Heller, from NYU Langone Health in New York City, said bacteria living in the digestive system appear to have broad-ranging impacts on human health, and that they "eat what we eat."
"Research suggests that they thrive on plant fibers -- such as those found in fruits and vegetables, legumes, nuts and grains -- and that the typical Western diet, which is rich in fat, red and processed meats, cheese, sweets, refined grains and fast-fried junk foods, in a sense, poisons them," she explained.
In China, where the study was done, a traditional diet has been low in fat and high in carbohydrates. That, however, has been shifting to a diet higher in fat and lower in carbohydrates. At the same time, the rates of obesity and type 2 diabetes have also been rising, the study authors said.
To see if changes occur in the gut microbiome when people transition from a low-fat diet to a higher-fat diet, the researchers recruited about 200 young people, who weren't obese, for the study. Their average age was about 23 years old.
Li said their average fat intake before the start of the study was about 31 percent.
The study volunteers were randomly placed into one of three groups for six months. One group ate a diet comprised of 20 percent fat, another ate 30 percent of their daily calories from fat, while the third had a 40 percent fat diet.
The researchers altered carbohydrate intake -- things like rice and wheat flour -- to make up for the changes in fat intake. The amount of fiber and protein in the diets stayed essentially the same.
All three groups had weight loss, but the lowest-fat group lost the most weight and had the greatest reductions in waist circumference, total cholesterol and bad cholesterol. The low-fat diet group also had an increase in gut bacteria that have been linked to lower cholesterol levels.
Those on the higher-fat fare had an increase in a different type of gut bug -- one that's been linked to higher cholesterol levels. Their diet was also associated with "significant" changes in long chain fatty acid metabolism, producing higher levels of chemicals that are thought to trigger inflammation.
Li said the findings may be relevant in developed countries where fat intake is high, but that further research needs to be done to see if similar changes occur in different populations.
"We suggest that fat intake for a general healthy population should not be more than 30 percent of total energy -- at least in Asian populations," Li said, and added that most fat should come from healthy fats, such as soybean, peanut or olive oil.
Nutritionist Heller said it's important not to "interpret the findings of this study to suggest that dietary fat is unhealthy. We need to eat fats to be healthy, unsaturated fats in particular."
But, she added, you can have too much of a good thing. "Fad diets rich in animal fats -- such as 'Keto' or 'Paleo' -- over time, are likely to be deleterious to the gut microbiome and subsequently increase the risk of inflammation and chronic diseases," Heller said.
To keep your microbiome happy and healthy, Heller recommended eating more vegetables, legumes, fruits, grains and nuts, while avoiding processed meats, limiting red meat and cheese, and balancing your intake of fats, carbohydrates and protein.
Results of the study were published online Feb. 19 in the journal Gut.
Evening primrose oil is extracted from the seeds of evening primrose (Oenothera biennis), a plant native to North America. It gets its name from the yellow blossoms which bloom in the evening. The oil contains gamma-linolenic acid (GLA), an omega-6 fatty acid that has both anti-inflammatory and analgesic (pain-relieving) properties.
Alternative practitioners believe that evening primrose oil can aid in the treatment of numerous health conditions, including acne, diabetic neuropathy, eczema, osteoporosis, psoriasis, premenstrual syndrome (PMS), and rheumatoid arthritis.
Evening primrose oil is not an essential oil commonly used for aromatherapy but one that can be consumed orally. It may cause side effects if overused and can interact with certain medications, including blood thinners and nonsteroidal pain relievers.
Evening primrose oil has been promoted as an effective treatment for a variety of ailments, including eczema and breast pain, since the 1930s. Many of these benefits are attributed to GLA, a fatty acid found in soybeans, walnuts, seeds, and vegetable oils (like rapeseed, canola, and linseed oil). Some the claims are better supported by research than others.
Evening primrose oil has long been used by women to treat hot flashes during menopause. Hot flashes are a form of flushing caused by reduced levels of the hormone estradiol.
While the body of evidence remains mixed, a 2013 study in the Archives of Gynecology and Obstetrics that found that a daily, 500-milligram dose evening primrose oil provided modest relief of hot flashes after six weeks.
Although the severity of hot flashes improved when compared to women provided a placebo, the duration and frequency of the episodes did not.
Evening primrose oil is also sometimes used to alleviate menstrual cramps and premenstrual syndrome (PMS). To date, there is no conclusive evidence to support these claims.
It was in the 1980s that evening primrose oil was heavily touted as an effective treatment of eczema by Canadian entrepreneur David Horrobin (1939-2003). Despite a positive response from consumers, many of the claims since been debunked in research.
According to a 2013 review of studies from the University of Minnesota Medical School, evening primrose oil proved no more effective in treating atopic eczema than a placebo in each of the seven reviewed trials.
Many of the same conclusions have been drawn when investigating the effectiveness of evening primrose oil in treating psoriasis or acne.
Rheumatoid arthritis is a type of autoimmune arthritis primarily affecting the joints. Some studies have suggested that GLA can reduce pain and improve function in people with mild to moderate rheumatoid arthritis. Most of the results to date have been modest at best.
A 2011 review of studies from Australia concluded that GLA found in evening primrose, borage seed, or blackcurrant seed oil provided "moderate" relief of pain and disability in people with rheumatoid arthritis.
The most promising results were seen in people who concurrently used nonsteroidal anti-inflammatory drugs, triggering a modest improvement in morning stiffness and joint articulation.
An increased intake of unsaturated fat is associated with a reduced risk of osteoporosis (bone mineral loss), especially in postmenopausal women. Primrose oil is almost entirely unsaturated fat and is believed by some to counter the bone loss seen in women with osteoporosis
An 18-month study from South Africa reported that the combined use of primrose oil, fish oil, and calcium supplements either slowed or reversed bone loss in older women (average age 79) compared to match set of women given a placebo.
According to the research, the women given primrose oil, fish oil, and calcium experienced an increase of femoral (thigh) bone density of 1.3 percent (versus a loss of 2.3 percent in the placebo group). While the bone density of the lumbar spine remained unchanged in primrose oil group, the placebo group experienced a decrease in bone density of 3.2 percent.
It was in 1993 that evening primrose oil was first proposed as a possible treatment of diabetic neuropathy (DN), an often debilitating nerve pain mainly affecting the feet and legs. Since then, there has been evidence to support some of these claims.
A 12-month study from India, involving 80 people with severe DN, concluded that a daily 500- to 1,000-milligram dose of evening primrose oil combined with 400 milligrams of vitamin achieved pain relief in 88 percent of the participants.
However promising, the conclusions were limited by the lack of a control (placebo) group to make an evaluative comparison. Still, the findings were significant enough to warrant further research.
Possible Side Effects
Like most supplements, there hasn't been much research assessing the long-term safety of evening primrose oil. In some cases, primrose oil may cause side effects such as stomach upset, headache, nausea, and diarrhea. Most of the side effects are low-grade and resolve on their own once the treatment is stopped.
There are certain medical conditions for which evening primrose oil may pose serious health risks. Among them:
Evening primrose oil may increase the risk of bleeding in people with bleeding disorders or those taking anticoagulants ("blood thinners").
If you have upcoming surgery, you should stop taking evening primrose oil two weeks beforehand to prevent excessive bleeding.
People with seizure disorders and who take medications for schizophrenia should avoid evening primrose oil as it may increase the risk of seizures.
Pregnant women should not take evening primrose oil as it may increase the risk of miscarriage or induced labor.
Evening primrose oil can interact with a significant number of medications, either reducing the drug's efficacy or triggering side effects (primarily bleeding or seizures). These include:
Advise your doctor if you are taking evening primrose oil—or any supplement—to avoid drug interactions and potentially serious side effects.
Dosage and Preparation
As a dietary supplement, there are no universal guidelines directing the appropriate use of evening primrose oil. Generally speaking, a daily dose of 500 milligrams is considered safe in adults, although many can tolerate up to 1,300 milligrams daily without any side effects. Due to the lack of research, evening primrose should be not be used in children.
Evening primrose oil is available in many health food stores or pharmacies and is typically sold in gel cap form. Bottled primrose oil is also available but is more difficult to accurately dose.
What to Look For
Dietary supplements like evening primrose oil are not required to undergo the rigorous testing that pharmaceutical drugs do. Instead, the U.S. Food and Drug Administration (FDA) imposes certain standards regarding the manufacture and labeling of the supplement. Even so, there is often considerable variation in the quality of supplements like evening primrose oil.
To ensure quality and safety, only buy supplements that have certified by an independent certifying body, such as the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab.
If you are strictly vegan or vegetarian, only choose brands labeled "vegetarian safe" or "vegetarian soft gels." Unless this is stated clearly on the label, the capsule may be made with animal-based gelatin (usually beef or pig).
How long does evening primrose oil last?
Evening primrose oil contains a lot of unsaturated fats that are susceptible to oxidative deterioration. Because of this, the concentration of seed oil content, including GLA, tends to drop after three to four months even with refrigeration.
To extend the shelf life of the oil, keep it in its original container (typically blue to prevent sun exposure) and store it in the refrigerator. Although primrose oil can keep for up to six months in the refrigerator, buy only as much as you can use within three.
How can you tell if primrose oil has gone bad?
Any product rich in unsaturated oil can go rancid, including bottled primrose oil and primrose oil gel caps. Because primrose oil has only a faint scent, it can often be difficult to tell if it has gone bad. It may darken or smell funny, but not always. As such, you should always play it safe and discard any supplement after its use-by date.
Most of us have spent at least some time lately thinking about losing those few extra pounds we put on over the holidays. We know we need to eat healthy and exercise, but what if we could add some nutrients to our daily regime to give our metabolism a boost? Fortunately, we can.
Before I share the best nutrients to boost our metabolism, let’s take a look at what exactly “metabolism” means. Most people throw the word around without really knowing much about it. Metabolism is the process by which the body breaks down food and nutrients for energy and for various bodily functions. Once we understand this concept it’s easy to realize that boosting our nutrition by adding various nutrients to our daily regime can help improve metabolism.
While a deficiency in any nutrient can play a role in impairing metabolism, digestion or energy functions in the body, the reality is that some are more important than others. The main nutrients needed to improve metabolism include:
The B-Complex vitamins are arguably the most important nutrients for a healthy metabolism. That’s because they literally boost the energy centers of our cells, known as mitochondria, which fuel every cellular function in the body. Vitamin B1, also known as thiamine, helps the body metabolize carbohydrates, fats and proteins.
Vitamin B6, also known as pyridoxine, is necessary for the proper metabolism of proteins. Vitamin B12, also known as cyanocobalamin, is needed for the metabolism of protein and fats. But, Vitamin B12 cannot function properly without B9, or folate, which is needed to ensure B12 works properly. Because the B-Complex vitamins work best together and supplementing with one or more can result in deficiencies of the others, it is best to take a B-Complex supplement rather than just individual B vitamins. They usually come in 50 milligram or 100 milligram products. Follow package instructions for the product you select. Some of the best food sources of B-vitamins include: apples, bananas, brown rice, grapes, nuts, seeds, spinach, squash and watermelon.
Research in the American Journal of Clinical Nutrition found that calcium, in conjunction with vitamin D, increases weight loss in those seeking to lose weight. The recommended daily dose of calcium varies between 800 to 1500 mg for adult men to post-menopausal women, with premenopausal women in the middle of that spectrum. The best food sources of calcium, include: almonds, almond butter, broccoli, carrot juice, carrots, dark leafy greens, kale, kelp, navy beans, oats, sesame seeds, sesame butter (tahini), soymilk and tofu (organic only since soy is heavily contaminated by genetically-modified organisms—GMOs), wild salmon and sardines.
Needed for healthy cellular functioning and for transporting oxygen throughout the body, including to muscles to help build healthy muscles, iron is necessary for a strong and healthy metabolism. The Recommended Dietary Allowances (RDAs) of Iron range from 8 to 18 milligrams for adults, with women typically needing more than men, and menstruating women needing more than non-menstruating women.
While many health professionals advise people to obtain heme iron from meat sources such as red meat, liver, poultry and fish, as they claim it is better absorbed, non-heme (plant-based) iron sources contain vitamin C, which improves absorption. Additionally, red meat, organ meat and poultry sources of iron typically contain excessive hormones, saturated fats, antibiotics and other substances that may negate their value. Non-heme sources of iron include: prunes, raisins, figs, apricots, bananas, walnuts, kelp, beans, lentils, dark leafy greens, asparagus and peaches. Incidentally, most of these foods also contain vitamin C, which helps with the absorption of iron in the body.
This mineral is necessary for the manufacture of energy and muscle formation in the body yet experts estimate that up to 80 percent of the population in North America are deficient in this essential nutrient. A typical dose of magnesium is 800 mg. daily and is usually taken with calcium supplements. Magnesium is found in almonds, sesame seeds, sunflower seeds, almonds, figs, lemons, apples, dark leafy greens, celery, alfalfa sprouts, brown rice and many other foods.
A low level of vitamin D has been linked with an increased amount of fat. It’s not clear whether increased fat causes low vitamin D levels or vice versa, but I believe that low vitamin D levels may lead to increased fat. That’s because some studies, like one published in the medical journal Clinical Calcium, found that vitamin D helps to control blood sugar levels and reduce insulin resistance in diabetics, meaning it makes the body respond better to its own hormone, insulin.
Moderate sunlight exposure, which is difficult to get this time of year, along with fish, liver and egg yolks are the primary food sources of vitamin D. Supplementation with D3, known as cholecalciferol, the type of vitamin D that has been used in most studies showcasing the vitamin’s benefits, is recommended. However, it is usually sourced from fish so you may wish to choose synthetic vitamin D2, ergocalciferol, if you are vegan. Most health professionals recommend 800 to 2000 IU daily; however, stick to the lower dose if you choose synthetic vitamin D2.
Vitamin C plays a big role in supporting healthy immune function. It is necessary for bone structure, skin integrity, and iron absorption, according to a study published by the Harvard Medical School.
If you are wondering how much vitamin C you should actually get, registered dietitian Summer Yule, MS, RDN, suggested that the recommended daily amount for adults is 90 milligrams for men and 75 milligrams for women. Although the vitamin is available through supplementation, Yule told INSIDER that vitamin C is also obtainable through fruits and vegetables, and restricting these items can actually put a person at risk of deficiencies.
Most people get enough vitamin C through a balanced diet. But to make sure you are getting enough vitamin C in your diet, INSIDER spoke to some dietitians and physicians about what the warning signs are if you’re not actually getting enough.
You can experience hair breakage
“Hair breakage can be a sign of vitamin C deficiency,” suggested registered dietitian nutritionist Cassie Berger, MS, RDN.
The vitamin is necessary for collagen production, which provides the structure needed for strong hair, nails, and skin.
Your skin can become dry
“A great way to protect your skin from over-drying during the winter is to get enough vitamin C,” explained Berger. Vitamin C aids in the production of sebum, she told INSIDER, which provides a protective oil layer for our skin.
You can experience rough skin with tiny bumps
“A vitamin C deficiency may cause rough skin with tiny bumps,” suggested registered dietitian nutritionist Rachel Fine, MS, RD, CSSD, CDN. “This is condition is known as keratosis pilaris and is sometimes called chicken skin,” she said.
Your gums can become painful and may bleed
“Vitamin C is necessary for healthy gums,” said registered dietitian Julie Upton, MS, RD. This vitamin is essential for the production of collagen, which is necessary for many organs and tissues, she told INSIDER.
You can bruise more easily
“Vitamin C is involved with collagen production, a component of blood vessels,” said board-certified emergency medicine physician Chirag Shah, MD. In the absence of adequate collagen synthesis due to a vitamin C deficiency, he explained that blood vessel integrity can suffer and sometimes result in increased and easy bruising.
Your wounds won’t heal poorly
“Through its impact is on collagen production, vitamin C deficiencies can also impact wound healing,” explained Shah. Vitamin C is important in enabling the healing process, he suggested, and a low vitamin C level will often show itself quickly through a poorly healing wound.
Vitamin C deficiency can lead to inflammation
“Vitamin C is a potent antioxidant that helps our body deal with inflammation,” said registered dietitian Ashley Weaver, MS, RD, CSSD. Inflammation can cause pain in joints, she suggested.
Vitamin C deficiency can lead to iron deficiency anemia
“Iron deficiency anemia can develop since low vitamin C intake decreases the absorption of non-heme sources of iron (such as from fortified cereals),” Yule said.
You can experience fatigue and irritability
“Lack of vitamin C will give you a case of fatigue and can even cause an irritable mood,” said registered dietitian Jenn Fillenworth, MS, RD. This is one of the earliest signs your vitamin C may be getting low, she suggested.
Scurvy is the most severe form of vitamin C deficiency
“Scurvy is the most severe form of vitamin C deficiency,” Fillenworth told INSIDER. Though it is rare, symptoms of scurvy develop after several months of being vitamin C deficient and include bruising, bleeding gums, fatigue, rash, muscle weakness, and coiled hair, she said.
THURSDAY, Sept. 20, 2018 (HealthDay News)
Different from osteoarthritis, which is the wear-and-tear breakdown of joint cartilage experienced over time, rheumatoid arthritis, or RA, is an autoimmune disease that causes both pain and intense fatigue.
When you're in the throes of a flare, exercise may seem like mission impossible and you might be advised to rest until it passes. But exercise is an essential part of an overall treatment plan to ease RA symptoms and improve mobility. Aim for a weekly routine that includes stretching, cardio and strength training.
Stretching boosts flexibility and range of motion. First, warm muscles with 5 minutes of light movement, then do a series of stretches to target all muscle groups. Always hold each stretch for 20 seconds. Yoga and tai chi are specific activities that increase flexibility and may even help ease the emotional stress of RA. To learn the basics, take a class or work one-on-one with an instructor, at least at first.
You can get the benefits of cardio with low-impact exercises, which are easier on your joints than a pounding activity like running. Walking is great, but swimming and water workouts put even less stress on joints because of the buoyancy of the water.
Support your joints by strengthening the muscles around them with resistance exercises. You can use stretchy resistance bands if weights are too hard to manage. Pay special attention to the muscles surrounding the joints most affected by rheumatoid arthritis, but don't neglect other muscle groups.
Work with your rheumatologist or a physical therapist familiar with RA to develop an individualized plan and ask how you should tailor your activities when a flare strikes.
Source From: https://consumer.healthday.com/bone-and-joint-information-4/rheumatoid-arthritis-news-43/exercising-with-rheumatoid-arthritis-736344.html
Healthy people with a low risk of cardiovascular disease may still need to keep a close eye on their cholesterol, according to new research.
A study(link opens in new window), published recently in the journal Circulation, found that otherwise healthy people with high LDL cholesterol levels are at higher risk of dying from cardiovascular disease than those with lower LDL.
Often called “bad cholesterol,” LDL contributes to fatty buildups in arteries, which increases the risk for heart attacks, strokes and peripheral artery disease.
“Even if you have a low 10-year risk, that doesn’t eliminate the long-term risks of having high cholesterol levels and significantly poorer cardiovascular health,” said Dr. Shuaib Abdullah, the study’s lead author.
Researchers looked at data from 36,375 patients in the Cooper Center Longitudinal Study. Participants had no history of cardiovascular disease or diabetes and were deemed to have a low 10-year risk of developing cardiovascular disease.
After following participants for about 27 years starting in their 30s or 40s, researchers found that people with LDL levels of 160 or higher had a 70 percent to 90 percent higher risk of dying from cardiovascular disease compared to people with LDL below 100.
“There’s controversy within the medical community about what the LDL cutoff level should be, when patients should be treated, and if they should be treated at all,” said Abdullah, an assistant professor of internal medicine at UT Southwestern Medical Center in Dallas. “But this study shows a marked increase in death from cardiovascular disease and coronary heart disease at the 160 level.”
An estimated 28.5 million Americans have total cholesterol levels of 240 or higher, which roughly corresponds to an LDL level of 160 or higher, according to the study.
Abdullah said the study serves as a reminder that all adults should get regular cholesterols tests no matter how old they are. “A lot of patients with high cholesterol don’t know it until they have a heart attack,” he said.
Guidelines recommend people have their cholesterol checked every four to six years starting at age 20.
The study also showed an increased risk for people with non-HDL cholesterol readings above 160. Non-HDL levels are a person’s total cholesterol minus their HDL, the “good” type of cholesterol that helps the body get rid of some of the harmful LDL. Abdullah said past studies have shown non-HDL levels might be a better marker for cardiovascular risk than LDL in patients with additional risk factors.
Dr. Christie Ballantyne, who was not involved in the new research but coauthored an accompanying editorial(link opens in new window), said the study provides “more important information for the patient-doctor decision-making process.”
“A study like this helps doctors say, ‘Your risk has increased and there are things we can do to treat that risk, whether it’s lifestyle modifications or using medications like statins,’” said Ballantyne, chief of cardiology and cardiovascular research at Baylor College of Medicine in Houston.
Ballantyne said the new research shows that even healthy people should be following recommendations for ideal cardiovascular health, such as not smoking, managing blood pressure and staying physically active.
“Most cardiovascular disease is preventable, especially if we get patients and health care providers the right information so they can make the best decisions,” he said.
Source from: https://www.heart.org/en/news/2018/08/20/bad-cholesterol-can-be-deadly-in-otherwise-healthy-people
Obesity and OA are two interconnected health care problems affecting a large proportion of the adult population worldwide, however studying causality in this association is difficult due to confounding factors. To test the hypothesis that the association between obesity and OA is causal, investigators used a method know as 'mendelian randomization', which uses genetic variants to investigate whether a biomarker has an effect on the risk of developing disease.
"Obesity in both childhood and adulthood is an important public health issue," said Professor Johannes W. Bijlsma, EULAR President. "These data showing a causal relationship with osteoarthritis should add further impetus to tackle the issue of obesity and reduce related disability."
Results of the study indicated that adult body mass index (BMI) significantly increased the prevalence of self-reported OA, knee OA or hip OA by 2.7%, 1.3%, and 0.4% per unit (1 kg/m2) increase in BMI respectively. Childhood BMI significantly increased the prevalence of self-reported OA, knee OA or hip OA by 1.7%, 0.6%, and 0.6% per BMI unit respectively. No associations were found between either adult or child BMI and hand OA, which contradicts previous cohorts. Investigators suggest that this could be explained by the impact of various confounding factors such as manual work or related socio-economic factors. Finally, no relationship was found with traumatic eye injury which was used in the study as a negative control.1
"Our results suggest the effect of adult BMI seems to be stronger on knees, whilst childhood BMI might impact both knee and hip osteoarthritis risk similarly," said Professor Prieto-Alhambra (senior study author). "Interestingly our findings contradict previous studies that found an association between obesity and hand osteoarthritis."
Investigators used data from two genome wide association studies (GWAS) which identified 15 and 97 specific gene changes, known as SNPs (single nucleotide polymorphism), associated with childhood and adulthood BMI respectively. They then used a separate GWAS of 337,000 unrelated individuals in the UK BioBank. Within this data they identified 13/15 childhood obesity SNPs and 68/97 adulthood obesity SNPs and then analysed the association between these SNPs and self-reported osteoarthritis, as well as hospital data for knee, hip and hand osteoarthritis. Associations with negative controls (myopia, left-handedness, and traumatic eye injury) were all inexistent as expected.