Laryngopharyngeal reflux (LPR) is a clinical condition that represents the return of gastric contents into the space of the larynx and hypopharynx, where it makes close contact with the tissues of the upper aerodigestive tract (1). Two theories explain the pathogenesis of reflux laryngitis. The first is the theory of direct injury to the mucosa of the larynx and surrounding tissue by acid and pepsin. This results in damage to the mucociliary transport and accumulation of secretions in the throat, which causes additional irritation of the mucosa and contributes to the onset of symptoms of laryngopharyngeal reflux. Namely, the larynx does not have protective external cleaning mechanisms and saliva cover that neutralise acids, so the gastric refluxate remains undiluted for a longer period of time, resulting in tissue injury. The second theory that explains the pathogenesis of reflux laryngitis is the reflex theory. According to this theory, LPR occurs due to oesophageal reflux, which stimulates vagally mediated reflexes resulting in chronic throat clearing and coughing that leads to mucosal injury of the larynx (2, 3). Nine of the most common symptoms of LPR were quantified by Belafsky et al. (4) in the so-called reflux symptom index (RSI), and based on years of experience, he concluded that if the RSI is greater than 13, LPR can be suspected. It is necessary to score the severity of the symptoms using a scale of 0–5 (0 meaning no symptoms to 5 meaning severe symptoms). The most common symptoms of LPR are hoarseness, throat clearing, postnasal drip, swallowing difficulties, coughing after meals or upon lying down, feeling of choking, coughing attack, globus sensation, heartburn and chest pain. Belafsky et al. (4) quantified the eight most common clinical signs of LPR in the reflux finding score (RFS). If the RFS is greater than 7, suspicion of LPR can be raised. The doctor calculates the RFS based on the presence or absence and severity of clinical signs of LPR. Some of the most common clinical signs of the disease are vocal fold oedema, granulation tissue, laryngeal posterior commissure hypertrophy, erythema, subglottic oedema, diffuse laryngeal oedema, ventricular obliteration and thick endolaryngeal secretion (5). Considering the severity of the symptoms and the impact on the quality of life of the patients, LPR can be mild, severe or life-threatening. Mild LPR bothers patients but does not interfere with their daily activities. Severe LPR significantly impairs the quality of life and interferes with patients’ daily tasks and personal activities. Life-threatening LPR is present in patients with airway obstruction (6, 7).

There is no gold standard for the treatment of LPR. It is treated with changes in diet, lifestyle and drugs such as proton pump inhibitors (8). Dietary measures include avoiding tea, coffee, fatty and spicy foods, alcohol, chocolate and carbonated drinks. The intake of alkaline foods such as bananas and melons is recommended. As for drinks, only plain or alkaline water is recommended. Furthermore, food should be consumed in smaller portions, more frequently and should not be taken within two hours of bedtime. It is necessary to raise the head of the bed when lying down, and one should not lie down immediately after eating. If the person is a smoker, he or she must quit smoking (3, 9). In addition to conservative treatment, surgical procedures such as transoral fundoplication and magnetic sphincter augmentation (3, 10) can be performed on patients who are refractory to conservative therapy.

It is known that lifestyle and dietary habits, such as smoking, consumption of alcohol and of acidic, sweet and spicy foods play a significant role in the development of LPR. The food frequency questionnaire is commonly used to assess dietary habits in clinical studies and it estimates the frequency of consumption of beverages and foods (11, 12). Lifestyle habits, including eating habits, vary in different countries and are often culturally conditioned (13, 14). Therefore, eating habits should be studied separately for each region. Furthermore, the role of eating habits of patients with laryngopharyngeal reflux disease has been comparatively scarcely researched. In our study, we aim to investigate eating habits and their influence on the onset, course of disease, and the quality of life of patients with LPR in eastern Croatia.

In addition to pantoprazole and esomeprazole therapy, other proton pump inhibitors such as omeprazole, lansoprazole and rabeprazole have often been used in other studies. The success rate in treating LPR symptoms with these proton pump inhibitors ranges from 18 to 87 % without significant differences in treatment outcomes based on the therapy used (4, 22, 23). Comparable to the results of these studies and considering the treatment outcome through subjective assessment of quality of life using the LPR-HRQL questionnaire, in our study there was no significant difference in any of the sections of the LPR-HRQL questionnaire between patients who used esomeprazole and pantoprazole after 30 and 60 days of therapy. Additionally, the median value of the overall impact of acid reflux was lower after 30 and 60 days in both mentioned groups than the value of the initial examination (Table 1).

In the group of patients with LPR, there were significantly higher values (more frequent occurrence of symptoms, p<0.001) in all sections of the LPR-HRQL questionnaire at the initial examination than in the control group. It should also be noted that the most common symptom in the group of patients with LPR was hoarseness (Table 2). Patients with LPR had similar median values in all domains of the LPR-HRQL questionnaire to the values reported by other authors (18, 19). However, small differences were found between our study and a Swedish study (18), in which the results showed lower values ​​of all LPR-HRQL sections than in our study, which could be explained by different cultural settings and differences in dietary habits.

In the group of patients with LPR, the values ​​of all LPR-HRQL sections were significantly lower (p<0.001) after 60 days than the initial values (Table 3). Therefore, we can say that the recommended therapy with proton pump inhibitors along with instructions on diet and lifestyle changes was definitely successful. In their study, Carrau et al. (19) measured the LPR-HRQL at baseline, after 4 and 6 months, and the therapy used was a dose of 20 mg omeprazole twice a day. Our study shows a similar improvement in scores between the pretreatment and post-treatment status compared to Carrau's study, although the measurements were taken after 4 and 8 weeks. Furthermore, in our study, patients were given dietary and general lifestyle instructions in addition to the proton pump inhibitors as part of the treatment. Several studies using the LPR-HRQL and surgical procedures such as fundoplication for LPR treatment have also shown a significant improvement in scores before and after the procedure (24, 25).

We examined the dietary habits of participants with LPR and the control group using a modified food frequency questionnaire (FFQ). Compared to patients with LPR at the beginning of the research, the control group consumed significantly more frequently pudding, semolina, polenta, rice, corn (cooked/baked), cornflakes, oatmeal, muesli, sugar-free soft drinks, bananas, melons, watermelon, carrots, spinach, chard and lettuce. The group of patients with LPR symptoms consumed significantly more frequently sour cream (12 % fat), yogurt, acidophilus milk, kefir (2.8 to 3.2 % fat), fruit yogurt, white bread (pastries and puff pastry), carbonated soft drinks, fruit syrups (fruit concentrate), apples or pears, oranges, grapefruits, mandarins, peaches, nectarines, grapes, onions, garlic, breaded pork, bacon, cookies, margarine, oils and hamburgers (Table 4). According to the results, patients with LPR consumed significantly more frequently fatty, fermented, sweet, and acidic foods and acidic drinks, which can increase the number of proximal reflux episodes and are important risk factors for developing LPR (8, 26). Lechien et al. (15) developed the refluxogenic diet score as an objective assessment of the refluxogenic potential of the food. In our study, participants without symptoms of LPR consumed more food with low refluxogenic potential (corn, rice, oatmeal, bananas, melons, watermelon, carrots, lettuce and cereals), while participants with LPR symptoms consumed significantly more frequently food classified as high refluxogenic food according to the refluxogenic diet score (yogurt, pears, apples, oranges, grapefruits, mandarins, nectarines, peaches, bacon, pork, butter and cookies) (Table 4).

In addition to the proton pump inhibitors, patients with LPR received written instructions on diet and lifestyle changes. They documented their daily food intake and, according to the instructions, they were told which foods had low and which had high refluxogenic potential (15). The patients with LPR significantly reduced the frequency of consumption of a large number of foods considered highly refluxogenic according to the refluxogenic diet score (Table 5 and Table 6). Such a change in diet could have an effect on the reduction of LPR symptoms, i.e. a significant reduction in the values of all LPR-HRQL sections and an improvement in the quality of life, as can be seen in Table 3. It is very important to give patients clear instructions on how to change their lifestyle and diet, to encourage them to write down the foods they consume every day and, of course, to monitor and advise them regularly. In their analysis of LPR therapy, Runggaldier et al. (27) particularly emphasise the importance of diet, which they consider one of the key factors for the success of LPR treatment. The meta-analysis by Min et al. (28) showed that avoiding fatty foods, chocolate and coffee while maintaining a Mediterranean diet and consuming alkaline water significantly reduced the symptoms and clinical signs of LPR. However, although the emphasis is on lifestyle and diet changes, the patients in our study took proton pump inhibitors daily, which could have contributed to better LPR-HRQL results. The study by Yang et al. (29) is also of interest, in which they compared the treatment of LPR by dietary and lifestyle changes with medication treatment. As much as 95 % of participants in the group that accepted diet change reported subjective improvement of LPR symptoms after the treatment. On the other hand, in the group of participants treated solely with anti-reflux medications, only 48 % of participants reported an improvement.

One of the limitations of this study is that the dietary habits in this study are specific to the population of eastern Croatia and may be very different from those of other regions, but nevertheless it shows a difference in the consumption of certain food groups between participants with and without LPR. Furthermore, FFQ-m questionnaire has so far been validated only for the adolescent population and not for adults. Another limitation of this study is that the treatment outcome was assessed using the subjective LPR-HRQL questionnaire, which is still a subjective measure, and that the quality of life was compared only between the use of esomeprazole and pantoprazole. In addition, this study could be further adapted and extended by including an additional dietary questionnaire and comparing the quality of life after the use of different proton pump inhibitors available on the market.

Treatment with proton pump inhibitors at a dose of 20 mg twice daily and dietary and general lifestyle changes for a duration of two months reduced the symptoms across all domains of LPR and improved the quality of patients’ life. Patients with LPR consume more high-reflux potential foods and drink more carbonated beverages and juices than the healthy population, who consume more low-reflux potential foods and non-alcoholic beverages. Changing dietary habits to include low-reflux potential foods and water while avoiding acidic, spicy, fermented, sweet, fried foods, other high-reflux potential foods, carbonated beverages and juices significantly reduces symptoms in all domains of LPR and improves quality of life. The use of LPR-HRQL as an instrument can facilitate future research that aims to evaluate and compare different LPR therapies.