Dear Doctor: Every now and then, I'll see a news story about the benefits of daily aspirin. A recent story linked it to a lower risk of cancer. What gives? Just how healthy is aspirin?

Dear Reader: We've long known that aspirin can reduce the chances of heart attack and strokes in people at high risk for the conditions. In fact, studies on those benefits provided the first inklings of a decreased risk of cancer, especially colon cancer.

Although those studies themselves couldn't verify the benefit of aspirin, what we know about the drug supports such a connection. Aspirin inhibits cyclooxygenase-2, or COX-2, an enzyme important to the formation of inflammatory compounds. Hypothetically, the loss of these inflammatory compounds, called prostaglandins, may lead to decreased cellular replication and decreased recruitment of new blood vessels. That is, with a reduced ability to multiply and grow, cancer cells could have less of a chance to take hold.

One of the earliest assessments of aspirin's impact on cancer came from the Women's Health Study, which randomized 39,876 women to taking a placebo or 100 milligrams of aspirin every other day. The women were followed on average for 10 years, and the majority had additional follow up for 7 1/2 additional years. Researchers found little difference in the rates of breast, lung and many other cancers, but after 10 years, they found a 20 percent reduction in the rate of colon cancer among those taking aspirin. The decrease of colon cancer was even greater among women who continued taking aspirin in the 7 1/2-year follow-up period. Note that there was a 14 percent increase in incidents of gastrointestinal bleeding among those taking aspirin versus placebo, but no change in death rates from bleeding between the two groups.

A 2016 study assessed aspirin use among patients in two large ongoing studies: the Nurses' Health Study and the Health Professionals Follow-Up Study. The combined studies looked at 88,084 women and 47,881 men who had been followed since the 1980s. Those who used aspirin two or more times per week, in either regular or "baby aspirin" doses, had a 19 percent reduction in colon cancer and a 15 percent reduction in stomach and esophageal cancers. However, this benefit was not noted for any other cancer.

Further, the decrease in colon cancer rates became significant only after five years of taking aspirin. The authors note that the population in these two studies was predominantly Caucasian and so may not be applicable to other races.

The same researchers recently presented a follow-up to this study to the American Association for Cancer Research. In this re-evaluation, the authors found a 31 percent decrease in the risk of colorectal cancers -- as well as reductions in breast, prostate and lung cancers. The reasons for such significant improvements are unclear.

Overall, the data point to a 20 percent reduction in colorectal cancer risk with the regular use of aspirin -- specifically 81 milligrams every other day -- but the numbers for other cancers are not convincing.

Be aware, however, of the risk of gastrointestinal bleeding. If you've had an ulcer or stomach problems with aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDS) in the past, daily aspirin use is not for you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I want to be better about protecting my skin from the sun, but the sunscreen aisle of our drug store is so confusing. Are all sunscreens the same and are they equally effective?

Dear Reader: Ultraviolet radiation (also referred to as UV rays) from the sun is the No. 1 cause of skin cancer, so your resolve to wear sunscreen is right on the mark. And with so many different products on the market, it's no surprise you're feeling overwhelmed.

Sunscreen is any cream, spray or lotion that combines specific ingredients that will prevent UV rays from reaching your skin. Two different kinds of UV rays -- UVA and UVB -- are targeted by sunscreen.

UVB rays cause sunburn. UVA rays, which reach into the deeper layers of your skin, cause premature aging. Both types of ultraviolet rays increase your risk of a variety of skin cancers.

You'll notice that sunscreen is rated by a number system -- SPF 15, for example -- which signifies its level of Sun Protection Factor. The SPF factor of a sunscreen refers to its level of protection against UVB rays only. It does not measure protection against UVA rays, which are equally harmful. To be sure you are getting protection against both UVA and UVB rays, choose a product whose label says "broad spectrum."

What the SPF number tells you about any brand of sunscreen is how it will protect your skin. Just multiply the amount of time it takes for your skin to begin to burn by the SPF number.

Let's say you typically start to turn pink after 10 minutes in the sun. A sunscreen with an SPF factor of 15 will, in theory, give you 150 minutes of protection. However, numerous factors are at play. Did you go swimming? Are you sweating? Did you put on enough sunscreen? Did it rub off on your hands or clothes? The rule of thumb put forth by skin cancer specialists is that an application of sunscreen lasts no longer than two hours. And if any swimming or sweating or rubbing occurred, reapply liberally and often.

The Food and Drug Administration, which regulates sunscreen products in the United States, recommends that you use an SPF of at least 15. But the experts at the American Academy of Dermatology say an SPF of at least 30 is the safest bet.

So which sunscreen should you choose and what's the right way to use it?

-- Go for one that's labeled "broad spectrum," so you're shielded against both UVA and UVB rays. Waterproof formulations are best. And remember -- SPF 30 or higher.

-- Apply the sunscreen 15 minutes before you go out. Yes -- before going into the sun.

-- It takes about 3 tablespoons to coat all exposed skin, including the tops of your ears, the back of your neck, your hands, your feet and any exposed scalp.

-- Don't forget to protect your lips -- products rated SPF 30 or more will do the trick.

-- Remember to reapply as needed.

Even with sunscreen, be sure to wear loose clothing and a hat. And stick to the shade for added protection.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: My mother is suffering from dementia and is increasingly difficult, but I'd hate for her to be given antipsychotics. Isn't there anything else that could be done to keep her calm?

Dear Reader: My heart goes out to you and your family. Dementia is one of the most difficult diseases to deal with -- for both patients and their loved ones. The loss of memory and the inability to incorporate new information is a struggle for many elderly patients. Some are able to cope with the loss of memory, but for others, the chaos of a poorly interpreted world causes agitation, irritability and anger.

Patients often scream about problems that aren't even part of their present reality -- leaving family members and health care staff struggling to manage their seemingly irrational agitation. Nursing homes in particular often request some form of treatment, whether it be restraints or medication, to calm these patients and to protect their employees.

Doctors often prescribe benzodiazepines or antipsychotic medications for such cases, but, of course, they have side effects. Most notably, they sedate patients to such an extent that their perception of reality is further altered. Further, antipsychotic medication has been linked to an increased risk of stroke and death.

There may be a better way. Many nursing facilities are now implementing a new program called Oasis. This program assesses both the biologic and psychological needs of the patient, shifting the emphasis away from a person's disabilities and focusing on his or her personhood. Early results are promising.

A 2017 study assessed the implementation of Oasis in 93 Massachusetts nursing homes, during which program coordinators and two to three staff members were trained in how to communicate with people suffering from memory impairment. These caregivers then helped train others within the nursing facility. Implementation of the Oasis program was verified by staff completion of webinars, trainer support meetings and training modules.

In comparing those facilities to 831 nursing facilities in New York and Massachusetts that didn't implement the program, researchers found that the use of antipsychotic medications dropped by 22.3 percent in the Oasis facilities, compared to a 17.2 percent drop in non-Oasis facilities.

Note that the drop in antipsychotic use appeared to be largely related to national trends, meaning that due to the awareness of side effects, practitioners overall are prescribing fewer antipsychotic medications to nursing home patients with dementia. That said, the Oasis program did show an additional benefit, supporting the idea that better training of staff can reduce some of the behavioral disturbances seen in nursing homes.

Another option for agitated patients is the use of antidepressants known as selective serotonin reuptake inhibitors, or SSRIs. These drugs -- the best studied in this respect is citalopram -- can be comparable in efficacy to antipsychotic medications, but without the significant side effects.

Finally, exercise, music and pet therapy also play a role in decreasing the agitation seen in those with dementia. All of these are worth exploring as you seek to maximize your mother's quality of life.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)