August 2010

PAMF Researchers to Present Findings at American College of Epidemiology Annual Meeting

August 20, 2010

Findings Highlight Need for Intervention Programs Emphasizing Fitness, Nutrition

Lead researcher, Latha Palaniappan, M.D., M.S., and her team at the Palo Alto Medical Foundation Research Institute (PAMFRI) will present their most recent findings from three separate studies at the American College of Epidemiology  Annual Meeting in San Francisco, California, on September 11-14, 2010.

Each year, the American College of Epidemiology invites submission of research topics for their annual meeting from different areas, such as medicine, statistics, sociology, genetics, and biology. Dr. Palaniappan and her research team will deliver three poster presentations on the following topics: 1) methods for overcoming partially missing data, 2) colon cancer screening rates, and 3) cardiovascular disease prevalence rates.

PAMF is one of the nation’s earliest adopters and leaders in the use of electronic health records  (EHRs). Dr. Palaniappan and her team use de-identified data from the EHRs at PAMF to study trends in and risk factors for obesity, type 2 diabetes and cardiovascular disease.

Study investigates risk factors for and incidence of diabetes in Asian American subgroups.

Dr. Palaniappan is the primary investigator of the Pan Asian Cohort Study (PACS), a study funded by the National Institute of Diabetes, Digestive, and Kidney Disease to investigate risk factors for and incidence of diabetes in Asian American subgroups. Obesity, a major risk factor for diabetes, is most often defined by body mass index (kg/m2), and is calculated using measured height and weight. Body mass index is an important tool used by physicians to calculate risk for chronic diseases, such as diabetes and cardiovascular disease. For a variety of reasons, body mass index is sometimes partially missing within the EHR. Dr. Palaniappan and colleagues compared methods for overcoming partially missing body mass index data in the EHR. These findings will be applicable to researchers across the nation who study obesity as a risk factor.

Study uses EHRs to compare colorectal cancer screening rates at PAMF to statewide self-report survey data from the California Health Interview Survey (CHIS), the largest state health survey in the U.S.

While missing data is one limitation of  an EHR, EHRs also provides a great deal of information, such as the number of patients with up-to-date colorectal cancer screenings. Colorectal cancer is the second leading cause of death in the U.S., and routine screening is recommended for patients ages 50-75. Several national and state surveys collect self-reported information on colorectal screening use. However, survey data are thought to overestimate receipt of screening tests. Dr. Palaniappan collaborated with Dr. Annette Maxwell, a researcher at UCLA, to compare colorectal cancer screening rates at PAMF to statewide self-report survey data from the California Health Interview Survey (CHIS), the largest state health survey in the U.S. The colorectal cancer screening rates from CHIS self-report data were higher than screening rates at PAMF, suggesting that there is over-reporting in colorectal cancer screening utilization in self-reported survey data.

Study investigates prevalence of stroke, coronary heart disease, peripheral vascular disease (PVD) in Asian American and Non-Hispanic White (NHW) patients at PAMF.

Cardiovascular disease is the leading cause of death in California and the United States. Dr. Palaniappan received a grant from the American Heart Association to investigate the prevalence of stroke, coronary heart disease (CHD) and peripheral vascular disease (PVD) in Asian American and Non-Hispanic White (NHW) patients at PAMF. There are considerable differences in Asian American subgroups with regard to stroke, CHD and PVD. Filipinos and Asian Indians are much more likely to develop CHD than other Asian subgroups and NHWs. While high rates of CHD among Asian Indians are increasingly recognized, Filipinos are less well studied. Dr. Palaniappan believes that future research should study Asian subgroups separately to better understand variation in disease patterns.

The American College of Epidemiology’s annual meeting will provide an important opportunity to present PAMFRI’s research findings and to raise awareness of health issues affecting patients.

Dr. Palaniappan was supported in part by a grant from the American Heart Association (0885049N ) and a grant from the National Institutes of Health  (5R01DK081371-02).

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Indoor Tanning Increases Risk of Cancer in Teens

August 17, 2010

Teenagers are especially at risk for problems with sun exposure and future skin cancer, according to Amy Adams, M.D., Ph.D., a dermatologist at the.Palo Alto Medical Foundation (PAMF). “Teens are starting to get lots of sun at an earlier age, and they don’t recognize this can cause cancer and sun damage.”  This increasingly includes indoor tanning, says Dr. Adams.

“Teenage girls are at tremendous risk of skin cancer from indoor tanning,” says Dr. Adams. “There are several important studies that have shown that out of the millions of people that do indoor tanning, three-fourths of them are teenage girls. These young girls are at a huge risk to get basal cell carcinoma or squamous cell carcinoma, which are some of the most common skin cancers, and also melanoma, which is one of the deadliest skin cancers.” Dr. Adams says research has also shown that indoor tanning activity is particularly high among Caucasian girls who are in their teenage years through their 20s.

“Our review of seven studies showed a 75 percent increase in melanoma in people who are exposed to UV radiation from indoor tanning devices,” explains Dr. Adams. “So, in addition to protecting their skin from natural sun, we strongly recommend that people – especially young teens – avoid exposure and dangerous radiation that comes with indoor tanning.”

According to Dr. Adams, one of the reasons it is particularly important to avoid indoor tanning is because the devices emit wavelengths of light similar to what the sun emits – both UVA and UVB. “We know that UVB normally causes tanning and burning, and is also a risk for some skin cancers,” says Dr. Adams. “UVA is the same in terms of risk for some skin cancers and also photo aging. We have a known entity in the sun in terms of how many minutes or length of time it may take to get some sun damage. However, indoor tanning devices are quite unregulated in terms of the energy they produce. They could have similar or much higher levels of radiation than the sun. Therefore, it’s particularly important to avoid indoor tanning because there’s no strong data to know how much energy you are giving yourself.”

Indoor Tanning Regulation

The Food and Drug Administration (FDA) is considering modifying how indoor tanning equipment and facilities are classified. According to Dr. Adams, there are different categories in which the instruments can be classified, depending upon their risk. “Currently, tanning beds are listed only as a Category 1 instrument, which would be similar to something like a bandage,” explains Dr. Adams. “However, we clearly know that these instruments pose a very high health risk of causing cancer – especially for our teens – and  because of the high risk potential for skin cancer, the FDA plans to upgrade the category classification. The Palo Alto Medical Foundation strongly supports the FDA’s efforts to restrict the use of indoor tanning devices.

Although the World Health Organization (WHO) has called for a restriction on use of indoor tanning by minors because of the high risk for skin cancer, only 31 states in the United States regulate indoor tanning use by minors.

The American Academy of Dermatology Association (AADA) opposes indoor tanning and supports a ban on the production and sale of indoor tanning equipment for non-medical purposes.

Suggestions for Teens on Tanning and Sun Safety

Dr. Adams says teenagers are interested in saving time and doing things they think will improve their appearance – such as tanning – in part, because of messages they  see in the media. “Indoor tanning can be alluring to teens because it is secretive and only takes a few minutes,” she says.

“At the Palo Alto Medical Foundation Department of Dermatology, we strongly encourage our teens to not tan, whether it’s by the sun or an indoor tanning device. If they express a desire to become tan – or to have that appearance for an event, we often tell them, ‘Get a spray on tan or perhaps wear different type of clothing or something else to modify your appearance – but, please do not tan. It’s too dangerous for you in causing potential skin cancer and skin aging.’ “That’s our motto – no indoor tanning. And always, wear sunscreen, protective clothing and a hat.”

YouTube Video of Dr. Adams Discussing Research Findings:

Link to video: http://www.youtube.com/watch?v=j0dL_VvkOC8

Additional Information from the American Academy of Dermatology:

Indoor Tanning Fact Sheet

Sun Safety Recommendations

ABCDEs of Melanoma Detection

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PAMF Research Institute Investigates Potential Explanatory Links between Obesity and Asthma

August 13, 2010

Jun Ma, M.D., Ph.D., PAMF Research Institute

Do allergies and insulin resistance play a part in rising incidence of obesity and asthma in the U.S.? Researchers at the Palo Alto Medical Foundation Research Institute (PAMFRI) recently completed analysis of national survey data and found no evidence that either insulin resistance or atopy (allergies) plays a role in the relationship between obesity and asthma.

The results, published online prior to print in the journal Allergy, are from an analysis of the National Health and Nutrition Examination Survey (NHANES), an on-going, population-based national survey conducted by the Centers for Disease Control and Prevention’s National Center for Health Statistics.

“Obesity is a known risk factor for developing and living with asthma, and atopy and insulin resistance are two of several hypothesized, yet unproven, mechanisms that may explain the obesity-asthma relationship,” said Jun Ma, M.D., Ph.D., who led the analysis by the department of Health Services Research at the PAMFRI. “Atopy is a major risk factor for asthma. Obesity and insulin resistance are closely related.  Unfortunately, data supporting these hypotheses are limited so we were highly motivated to investigate the role of atopy and insulin resistance as potential mechanisms.”

The investigation joins a small number of international studies as the first known population-based U.S. analysis aimed at exploring the potential explanatory roles of atopy and insulin resistance in the relationship between obesity and asthma.  Data for the analysis came from the 2005-2006 NHANES survey of 10,348 people of all ages.  The analysis included 4,493 adults (2,337 women and 2,156 men) aged 20 years and older who had completed the NHANES interview, representing nearly 200 million Americans. Their height, weight and weight circumference were measured. Additionally, they were tested for insulin resistance and specific IgE allergens (IgE, immunoglobulin E, are antibodies in the immune system) including dust mites, animal danders, fungi, grasses and trees.

In the study group, eight percent of participants had asthma; 67 percent were overweight or obese.  The prevalence of atopy (allergies) was 41 percent, and incidence of insulin resistance was 22 percent.

The analysis showed no apparent role of either insulin resistance or atopy in the obesity-asthma relationship.  Obesity was related to both atopic and non-atopic asthma (atopic asthma is also called allergic asthma and is a type of asthma that is triggered by allergens). Obesity’s relationship to asthma was independent of insulin resistance status.  No association of obesity was observed with atopy.  Further, insulin resistance was not related to asthma prevalence regardless of obesity status.

Dr. Ma cautioned that although the findings did not provide evidence of a possible role of atopy or insulin resistance linking obesity and asthma, additional research is necessary to confirm the lack of association.  She noted that NHANES participants are interviewed only once and not followed over time and confounding by factors other than those being studied is always a potentially major problem in observational studies. 

“The NHANES is a valuable data source for exploring different hypotheses but it is designed to provide a ‘snap shot’ of health, which inherently limits the ability to understand how and why diseases and medical conditions develop,” she said.  “Therefore, the findings should be confirmed by additional and more rigorous studies, such as prospective cohort studies and intervention trials.  Other potential mechanisms should also be explored, including obesity’s effects on the mechanics of breathing and airway inflammation, and the influences of common genetic pre-dispositions and lifestyle factors.”

Dr. Ma was assisted by her PAMFRI colleagues Lan Xiao, Ph.D., and Sarah Knowles, Ph.D.

The article has been published on-line ahead of print in the journal Allergy.  To view the document online, a reader can access the article via PubMed: http://www.ncbi.nlm.nih.gov/pubmed/Pub Med ID: 20456316

The citation is:  Ma J, Xiao L, Knowles SB. Obesity, insulin resistance and the prevalence of atopy and asthma in US adults. Allergy 2010; DOI:10.1111/j.1398-9995.2010.02402.x.

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