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Differences in Travel-Associated Diseases between Older and Younger Adults
Abstract & Commentary
By Richard R. Watkins, MD, MS, FACP
Division of Infectious Diseases, Akron General Medical Center, Akron, OH; Associate Professor of Internal Medicine, Northeast Ohio Medical University, Rootstown, OH
Dr. Watkins reports no financial relationships to this field of study.
Synopsis: This study analyzed prospective data from 1997 to 2009 on ill international travelers. Compared to younger travelers, those 60 years and older had a higher incidence of lower respiratory infections, high-altitude pulmonary edema, phlebitis and pulmonary embolism, arthropod bites, severe malaria, rickettsiosis, gastritis, peptic ulcers, esophagitis and gastroesophageal reflux disease, trauma and injuries, urinary tract infections, heart disease, and death.
Source: Gautret P, Gaudart J, Leder K, et al. Travel-Associated Illness in Older Adults (>60 y). J Travel Med 2012;19:169-77.
Currently adults aged 60 years and older represent 15%-30% of international travelers. This age group is believed to be at increased risk for travel-related illnesses for several reasons, including their increased probability of underlying medical conditions, waning immunity from previous vaccinations, reduced immune response to vaccines given prior to their trip, and a greater predisposition to acquiring certain diseases. Indeed, this is well known by those in the insurance industry who regularly charge older travelers much higher premiums than their younger counterparts. In this study, investigators sought to determine the range of illnesses among older adult travelers. They utilized prospective data from patients who presented to GeoSentinel sites from March 1997 to August 2009.
The GeoSentinel Surveillance Network is a group of travel medicine clinics on six continents where ill travelers are seen during or after traveling to a range of destinations. Patients were eligible to be included in the database if they crossed an international border and sought medical advice at a GeoSentinel clinic for a presumed travel-related illness, or had been diagnosed with a disease related to travel history by the clinic physician. Data collected included demographic information, travel data, reason for travel, inpatient or outpatient status, history of a pre-travel clinic visit, and travel-related clinical findings. Co-morbid illnesses and chronic conditions were not documented in the database.
A total of 63,076 ill adult travelers were included in the database, of which 7,034 were aged 60 years and older (8.4%). Compared to younger travelers, older patients were more likely to be male, reside in North America, travel for tourism, travel for a shorter duration, and less likely to have sought travel advice before their trip. Acute diarrhea was the most common illness in both groups, although it was comparatively less frequent among the older travelers. Respiratory illness was the second most common condition in the older group, while febrile systemic illness was second in the younger travelers. Illnesses that were significantly more common in the older group included lower respiratory tract infections, high-altitude pulmonary edema, arthropod bites, Plasmodium falciparum severe malaria, rickettsiosis, gastritis, peptic ulcer, gastroesophageal reflux disease, strongyloides, trauma and injuries, altitude sickness, vertigo, cerebrovascular accident, urinary tract infections, heart disease, phlebitis, pulmonary embolism, and death. Subanalysis revealed an inverse relationship between age and P. falciparum malaria and dengue among ill travelers (p < 0.001).
The main strength of this study was its multicenter design, which allowed for a large number of participants from many countries. It was limited because the data collected may not be representative of the overall population of travelers, and the results may not be generalizable to the illnesses usually seen at non-specialized primary care offices where mild or self-limited conditions present with more frequency. Also, underlying chronic diseases were not documented by GeoSentinel which does not allow evaluation of their impact on travel-associated morbidity. The authors concluded that older travelers have a higher relative proportion of life-threatening illnesses (lower respiratory tract infection [LRTI], high-altitude pulmonary edema, severe P. falciparum malaria, cardiovascular disease, and pulmonary embolism) and should be specifically targeted for prevention of such diseases.
It has become common to see adults aged 60 years and older in travel clinic. Individuals in this age group are believed to be at higher risk for travel-associated illnesses.1 Hence, it seems prudent that specific travel advice tailored to this age group be established, in addition to other routine precautions and interventions (i.e. vaccines) given to all travelers. The study by Gautret and colleagues provides useful data towards building this base of recommendations. It was a large multicenter study that used data collected from the GeoSentinel Surveillance Network, which is supported by the Centers for Disease Control and Prevention. The authors found that the spectrum of illnesses varied widely depending on the age of travelers after eliminating confounding factors, such as travel destination. Older travelers suffered more morbidity from age-related conditions, such as cardiovascular diseases. Another recent study confirmed this observation, wherein the main cause of death in travelers over age 65 was cardiovascular (70%), followed by infectious disease (12%).2 It was interesting that acute diarrhea occurred with less frequency in the group of older travelers. The authors speculate this was due to an increased likelihood of past exposure to pathogens or better adherence to reduced risky dietary exposures. Alternatively, the older travelers may have taken antibiotics and/or antimotility agents with more frequency. Given their greater proportionate morbidity from LRTIs, older travelers should take precaution against respiratory illnesses. The authors suggest good hand hygiene, use of disposable handkerchiefs, and face-masks in crowded conditions. Influenza was the most common vaccine-preventable disease in the study, supporting the recommendation that all travelers be given the influenza vaccine. Pneumococcal vaccination is another intervention older travelers can do to lessen their risk for LRTI, as can younger travelers with chronic illnesses. With the higher risk for severe illness from P. falciparum malaria in older travelers, malaria chemoprophylaxis along with insect repellant and mosquito nets should be emphasized.