Health risks of using natural gas appliances at home are low
Q: There is much mainstream news recently about the health risks of using natural gas appliances. I am 75 and have survived playing with mercury from broken thermometers as a child, a lifetime of cooking and home heating, and hot water from natural gas. I certainly don’t advise playing with mercury, but how seriously should I, and other apparent survivors, be about natural gas in our actuarial calculations?
A: The reason for concern with natural gas stoves is that there is evidence that children are more likely to develop asthma in homes that use natural gas stoves for cooking. This effect was strongest in multifamily homes and did not exist in one analysis concerning single-family homes. The effect is thought to be due to nitrogen dioxide (NO2), but benzene (from unburnt natural gas) and fine soot are other possible issues.
Long-term high exposure to NO2 is associated with chronic lung disease and reduced mortality, but these studies have been done based on air pollution, not home exposure from gas stoves. The magnitude of the risk from gas cooking is low, so I think the effect on your expected mortality is likely to be very low. I do not recommend changing your stove based on the expectation of a longer life.
A stove hood that vents to the outside dramatically reduces NO2 levels and reduces asthma risk (and the risk of your child with asthma having an attack). Alternatively, you can switch to an electric stove. (I’ll just note that induction cooktops heat up even faster than gas and are more efficient.)
Finally, playing with mercury is a bad idea, not because liquid mercury is dangerous, but because mercury vapor is. Broken thermometers or light bulbs should be promptly cleaned. Check with your local health department or online at tinyurl.com/mercuryspill on how to do so.
Q: My husband’s doctor is repeatedly pushing statins on my husband. His cholesterol was high in the past and is still slightly high (239 mg/dL — borderline high). I’ve checked the heart risk calculator. It said his risk is 22.1 percent and goes down
to 16.6 percent if he goes on statins, which is still considered high risk.
Also, my mother had heart surgery for a “widowmaker” (with 90 percent blockage), and she has been on statins for ages, so I’m thoroughly confused. Also, he has stage 3b chronic kidney disease, and I read that statins could cause problems with his kidneys.
Could you explain the benefit, if any, for him to be on statins? Also, my husband is adamant about not changing his diet. Thanks. I’m really at a loss and am not sure what is best for him.
A:
If there were a medicine that was 100 percent effective at preventing heart disease and had no side effects, we would recommend it for everyone. Sadly, that doesn’t exist. The
best we have right now is a class of medicines (statins) that reduce relative risk by about 25 percent and has side effects bad enough to make a person stop it, in about 1 percent to 5 percent of people. Because it is not perfectly effective and does have the possibility of serious side effects, we recommend treatment only in people with a high enough risk that the potential harms make treatment worthwhile.
Every person with known heart blockages, like your mother, is recommended for lifelong statin therapy if they can tolerate it and don’t have a good reason not to. People at a high risk, like your husband (22 percent is considered quite high), are also recommended treatment.
The calculator estimates 5.5 percent of people, like your husband, who are treated will not have a heart attack or die from heart disease if they take a statin, when they otherwise would have. For most people, that’s a good enough result to take the medicine, while other people prefer to take the risk. It is ultimately his decision to make.
Most North Americans can reduce their risk of heart disease quite a bit by improving diet, exercising more, quitting smoking and managing stress better. Often, when people make those changes, they don’t need statins anymore! Also, these lifestyle changes don’t have the risk of medication side effects. But, even if your husband doesn’t make any changes, just taking a statin daily will help.
If your husband likes sports, you might ask him which opposing hitter he would like his team to face: the one who bats .221 or the one who bats .166 — only the downside is that it isn’t a baseball game, it’s whether he gets a heart attack.
Finally, the existing data show statins are generally safe in people with kidney disease, although some need to have the dose adjusted if kidney function is worse than your husband’s. However, it’s very important to note that, overall, the risk of death is substantially decreased by taking a statin among people with kidney disease, because people with kidney disease are at a higher risk for heart disease and stroke, with which statins help.
Q: I’m curious about the effect of tart cherry juice on gout that you mentioned in a recent column. Any idea why? What’s unique in tart cherry juice? Does non-tart cherry juice work? What about tart strawberry or apple juice?
A:
There are several varieties of cherries, with most people being familiar with Bing and Rainier cherries. Tart (Montmorency) cherries have been touted as having many health benefits, but regular cherries show a reduction in gout attacks. In the study, 10-12 cherries twice daily reduced gout attacks by 35 percent. (People with diabetes might not be appropriate for as much fruit intake.) Unfortunately, alcohol and meals prone to cause gout flare-ups (such as shellfish) make the cherry intake less effective.
A separate trial on tart cherry juice did not find a benefit in reducing gout risk. Gout is caused by deposition of uric acid crystals, and most medications to reduce gout attacks focus on reducing uric acid in the blood. But there seems to be something specific in cherries — a class of compounds called anthocyanins (found in cherries in high levels) are known to have anti-inflammatory effects. Other fruits, specifically strawberries, grapes and kiwi, were tested and did not have the beneficial effects on the blood uric acid level that cherries did.
Cherries are not as effective as prescription medication, such as allopurinol, but may be helpful in people with very mild disease or who aren’t controlled with allopurinol.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Drive, Orlando, FL 32803.