Many travel insurance policyholders are putting themselves at risk by not disclosing pre-existing medical conditions new research has discovered. Figures published by Sainsbury’s Travel Insurance found that as many as 500,000 holidaymakers have taken vacations without making their travel insurance provider aware of a medical ailment they are suffering from. Back pain was one of the most common medical issues which travellers had failed to tell their insurer about with 254,000 people admitting to having travelled last year without telling their insurance company about their back issue. Travel insurance experts have warned that omitting details about your health, which you may believe is irrelevant to your travel policy, could end up costing you dear as a failure to disclose information can invalidate your cover. If this were to happen after falling ill abroad, the policyholder could be hit with the full extent of paying for medical treatment while abroad. Some of the reasons given for not fully disclosing medical conditions to insurers were that people felt uncomfortable discussing their personal health issues over the phone with a stranger, while others said they were afraid of being refused cover because of an ailment.