Zinc for colds

Zinc was recognized as an element in 1509 and as an essential mineral much later. In 1961, zinc deficiency was linked with hypogonadism. Zinc is included in almost all over-the-counter daily vitamins and mineral supplements, typically in the form of zinc oxide, zinc acetate, and zinc gluconate. Zinc is absorbed through the small bowel with an efficiency of 20%-40%. It is the second most important metal in the body after iron and is present in virtually 100% of proteins.

Zinc inhibits viral replication. Because of this, it has been investigated as a way to decrease the duration of symptoms from the common cold. With some evidence suggesting that it works, we know little about the right dose for zinc to exert its magical effects.

In a recently published systematic review, Singh and Das updated a previous Cochrane systematic review and, once again, evaluated the efficacy of zinc in reducing the incidence, severity, and duration of common cold symptoms (Cochrane Database Syst. Rev. 2013;6:CD001364). Studies were included if they were randomized, double-blind, placebo-controlled trials using zinc for at least 5 days for treatment or 5 months for prevention of the common cold.

Sixteen therapeutic trails involving a total of 1,387 people, and two preventive trials with 394 participants were included in the meta-analysis. Zinc came in the form of syrup, lozenges, or tablets. Zinc was associated with statistically significant reductions in theduration but not the severity of symptoms. The mean difference in reduction duration was 1 day (95% confidence interval, –1.72 to –0.34). After 7 days of treatment, significantly fewer subjects had symptoms. Zinc was associated with a reduced incidence of colds, absences from school, and receipt of antibiotics. Bad taste and nausea were significantly higher in patients treated with zinc. The authors suggested that there is a significant reduction in the duration of cold symptoms at a dose of at least 75 mg/day in the lozenge form.

Inhaled zinc can cause permanent anosmia, and so this delivery route was not investigated. Lozenges may be the best bet, since we know the daily dose should be at least 75 mg for treatment. For patients interested in using zinc for prevention, no clear dosage recommendations can be made. Megadose supplementation or high zinc intake has been associated with abdominal pain, diarrhea, nausea, and vomiting. Zinc may interfere with copper absorption, and high zinc intake (greater than 150 mg/day) can lead to copper deficiency and should be avoided.

Tomado: internalmedicinenews.com

By: JON O. EBBERT, 

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HPV vaccine doesn't promote risky sex

Young women who get the human papillomavirus (HPV) vaccine don't see it as a license to have more sexual partners or forgo condoms, a new study confirms.

The US Centers for Disease Control and Prevention calls for both girls and boys to be vaccinated against HPV, the sexually transmitted virus that causes cervical cancer.

Some parents and community groups have been concerned that the vaccine might promote risky sex.

But in the new study, even the small group of girls who misunderstood their risk of sexually transmitted infections (STIs) after getting vaccinated didn't change their behaviour as a result, researchers found.

"There are so many contributing factors to whether an adolescent decides to have sex or not, and whether they decide to limit their number of partners or use condoms," says Dr Jessica Kahn. "Getting a vaccine probably just plays a very, very small role in their decisions."

Kahn worked on the study at Cincinnati Children's Hospital Medical Center in Ohio.

Her team's findings are in line with another report that showed girls who had been vaccinated weren't more likely to get other STIs or become pregnant.

"To me, the issue is laid to rest," says Kahn. "As clinicians and researchers, we have no concerns that vaccination will lead to riskier sexual behaviours."

Maintaining their behaviour

She and her colleagues studied 339 young women between 13 and 21 years old who were getting their first of three HPV shots. Most of the women were black and came from low-income families.

The researchers surveyed participants about how important they considered safe sex to be, and how concerned they were about STIs. Then they asked the participants about changes in their sexual behaviour when the young women came back two and six months later for their next shots.

After getting the first vaccine, most young women agreed it was still necessary to use condoms and generally practice safe sex. On a scale from zero to 10, where lower scores indicate a better understanding of risks, participants scored a 1.6, on average.

Most study participants also understood that the HPV vaccine doesn't protect against other STIs, and they scored a 3.9 on their perceptions of STI risks, according to findings published in the journal Pediatrics.

"The vast majority of girls thought that safer sexual behaviours were still important after vaccination," says Kahn. But even those who didn't accurately perceive their risks weren't any more likely to start having sex or stop using condoms, her study shows.

Among women who say they had never had sex when they got their first vaccine, 20 per cent had become sexually active by the time the researchers checked in with them six months later.

Of those who were already having sex when the study started, close to two thirds said at their six-month visit that they used a condom the last time they had sex. About one third reported two or more sexual partners since their last visit.

"The findings strengthen a growing body of literature that indicates that getting HPV vaccination is very unlikely to change an adolescent's perception about risk and also their actual sexual behaviour," says Dr Amanda Dempsey.

Dempsey is a paediatrician and vaccine researcher at the University of Colorado, Denver and wasn't involved in the new research. She tells parents that young people's attitudes on sex are based on years of discussions about family values — so a shot shouldn't have a major effect.

Kahn says she is worried that parents' concerns about changes in sexual behaviour might still be keeping them from getting their children vaccinated.

HPV vaccination rates in the United States are relatively low. One in three girls between 13 and 17 years old had gotten all three shots in 2012, the researchers note.

Significant impact in Australia

In Australia, the HPV vaccine is given to girls and boys aged 12 and 13 years at school.

According to Dr Julia Brotherton of the Victorian Cytology Service in Melbourne, the rate of coverage in Australia is around 70 per cent.

"Vaccine uptake is fairly evenly spread across the socio-economic spectrum because of the school-based system," says Brotherton. "In the United States, it relies on parents to make an appointment, then a doctor has to administer it and it is then claimed from the insurer."

She says there has also been more of a focus on the benefits of the HPV vaccine in Australia.

Brotherton adds that since the vaccine was released on the market in 2007, the rate of HPV infections has declined.

"We've already seen rates of infection go down by 77 per cent, while genital warts have almost disappeared in young women and men," she says.

Two of the study's seven authors have received grants from the two companies that sell HPV vaccines, Merck and GlaxoSmithKline. The current study was funded by the US National Institutes of Health.

Tomado de: abc.net.au

Genevra Pittman and staff

Fecal immunochemical tests detect most colorectal cancers

Fecal immunochemical tests have an overall diagnostic accuracy of 95% for the detection of colorectal cancer, according to the results of a meta-analysis just published in the Annals of Internal Medicine.

The tests, which have already begun to replace the fecal occult blood test (FOBT) in national screening programs in the United States, Europe, and Asia, were found to be 79% sensitive and 94% specific for CRC.

"This systematic review and meta-analysis suggests that FITs [fecal immunochemical tests] have high accuracy, high specificity, and moderately high sensitivity for detection of CRC," Dr. Douglas Corley of the Kaiser Permanente division of research in Oakland, Calif., and his associates wrote (Ann. Intern. Med. 2014;160:171-81).

FITs are more sensitive at detecting both CRC and adenomas than the FOBT, they maintained, and are also more practical for people to perform at home, requiring only one or two stool samples and no special dietary or medication restrictions.

Despite a greater potential ease of use for mass screening, reports on the diagnostic performance of FITs have been inconsistent, the investigators explained. They therefore performed the meta-analysis to determine the overall diagnostic accuracy and factors affecting the tests’ performance. Nineteen trials were included that involved more than 113,000 individuals and provided data on eight different FITs available for use in the United States.

In addition to the sensitivities and specificities of FITs, positive and negative likelihood ratios (LR) were calculated to assess the ability of the tests to respectively "rule in" or "rule out" a diagnosis of CRC. The threshold set for a positive LR was a value above 5 and for a negative LR was 0.2. Pooled data from the trials showed a positive LR of 13.10 and a negative LR of 0.23.

Increasing the number of FIT samples did not affect the pooled sensitivities, specificities, positive LRs, or negative LRs of FITs for CRC. There also was no great difference in performance between the FIT brands evaluated in the studies. Dr. Corley and his associates pointed out, however, that head-to-head comparisons were not included in most studies so this finding should be interpreted with caution.

Diagnostic performance was affected by the cutoff values used to define a positive test, which might influence which test health systems decide to use, the researchers said.

"Health systems wishing to optimize use of a quantitative FIT should consider the tradeoff between increasing sensitivity (by lowering the cutoff threshold for a positive test) and the resulting increase in the number of positive results," they wrote. The latter could significantly impact colonoscopy resources if more procedures were indicated by a positive test.

The researchers recommended that health systems also look at individual studies comparing single or repeat testing, as the current data do not provide a definitive answer on the effect of sample number on the performance of FITs.

The National Institute of Diabetes and Digestive and Kidney Diseases and the National Cancer Institute funded the research.

By: SARA FREEMAN, Family Practice News Digital Network