Gastrointestinal [GI] disorders represent a major public health concern worldwide because of their high prevalence, recurrent symptom burden, impact on quality of life, and substantial healthcare costs. These disorders encompass a broad clinical spectrum, ranging from functional gastrointestinal disorders such as irritable bowel syndrome to chronic inflammatory conditions including inflammatory bowel disease, gastroesophageal reflux disease, and gastrointestinal malignancies. Recent evidence suggests that the burden of GI disorders is increasing, particularly in low- and middle-income countries undergoing rapid demographic, nutritional, and epidemiological transitions [1,2]. This growing burden highlights the importance of identifying modifiable determinants that may contribute to prevention, early intervention, and improved disease outcomes. The pathogenesis of GI disorders is multifactorial and involves a complex interaction among genetic susceptibility, environmental exposures, immune responses, gut microbial composition, and behavioral influences. A key mechanism underlying this interaction is the gut-brain axis, a bidirectional communication network that integrates neural, endocrine, and immune pathways to regulate gastrointestinal physiology. Disturbances in this axis have been implicated in both functional and organic GI diseases, linking psychological stress and behavioral disturbances with altered gut motility, visceral sensitivity, and symptom expression [3]. In addition, growing evidence has emphasized the role of the gut microbiota in maintaining intestinal homeostasis, regulating mucosal immunity, and influencing metabolic and inflammatory processes relevant to gastrointestinal health [4,5]. Among the potentially modifiable risk factors, diet quality has emerged as one of the most important determinants of gastrointestinal health. Dietary patterns influence gut function through several biological mechanisms, including modulation of microbial diversity, short-chain fatty acid production, intestinal barrier integrity, and inflammatory signaling. Diets rich in fruits, vegetables, whole grains, and other fiber-containing foods have been associated with favorable gastrointestinal outcomes, whereas dietary patterns characterized by high intake of processed foods, refined carbohydrates, and saturated fats have been linked to dysbiosis, chronic low-grade inflammation, and increased susceptibility to GI disorders [6]. These findings suggest that dietary quality is not merely a supportive factor, but a central component in the development and progression of gastrointestinal disease. Lifestyle-related factors also exert a significant influence on GI health. Physical inactivity, chronic stress, poor sleep quality, smoking, and alcohol use have each been associated with adverse gastrointestinal outcomes. Chronic stress can alter autonomic regulation, intestinal permeability, immune activity, and visceral sensitivity, thereby contributing to symptom generation and disease exacerbation [7]. Likewise, sleep disturbance has been associated with altered microbial balance and inflammatory activity, further strengthening the link between behavioral and physiological determinants of GI disease [8]. In contrast, regular physical activity appears to confer protective effects through improved gut motility, reduced inflammatory burden, and beneficial modulation of the gut microbiome. Although the independent effects of diet and lifestyle on gastrointestinal health have been widely studied, these factors rarely operate in isolation. In real-world settings, individuals are simultaneously exposed to multiple behavioral influences that may interact and produce additive or synergistic effects. However, much of the available literature has examined these exposures separately, resulting in a fragmented understanding of their collective role in GI disease development and progression [9]. This gap is particularly relevant in countries such as India, where rapid urbanization, changing food environments, reduced physical activity, and increasing psychosocial stress are reshaping disease patterns through an ongoing nutrition and lifestyle transition [10]. In view of these considerations, a multidimensional assessment of dietary quality and lifestyle factors is both relevant and necessary. Evaluating their combined influence may provide a more comprehensive understanding of modifiable risk factors and may support the development of integrated preventive and therapeutic strategies for gastrointestinal disorders. Therefore, the present study aimed to evaluate the combined and independent effects of diet quality and lifestyle-related factors on the incidence and progression of gastrointestinal disorders.

Study Design and Setting This study was designed as a prospective, observational, multidimensional analytical study conducted in the Department of Medical Gastroenterology at Konaseema Institute of Medical Sciences and Research Foundation, located in Amalapuram. The study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for reporting observational research. Study Duration The study was conducted over a period of one year, from January 2024 to December 2024. Study Population The study population comprised adult patients attending the outpatient and inpatient services of the Department of Medical Gastroenterology. Inclusion Criteria Adults aged ≥18 years Patients diagnosed with gastrointestinal disorders (functional or organic), including but not limited to: Irritable bowel syndrome (IBS) Gastroesophageal reflux disease (GERD) Inflammatory bowel disease (IBD) Chronic liver and other GI disorders Patients willing to provide written informed consent Exclusion Criteria Critically ill patients unable to participate in interviews Patients with severe psychiatric illness affecting response reliability Pregnant and lactating women Patients on specialized therapeutic diets (e.g., parenteral nutrition) Incomplete or missing baseline data Sample Size Estimation Sample size was calculated based on expected prevalence of gastrointestinal disorders and anticipated effect size of dietary and lifestyle factors on disease outcomes. Assuming a moderate effect size, 95% confidence interval, and 80% power, the minimum required sample size was estimated to be124 participants (to be calculated using appropriate statistical formula/software). An additional 10–15% was added to account for dropouts. Sampling Technique A systematic random sampling method was employed to recruit eligible participants from outpatient and inpatient registries. Consecutive patients meeting inclusion criteria were approached until the desired sample size was achieved. Data Collection Tools and Variables Data were collected using a structured, pre-validated questionnaire and clinical assessment forms, comprising the following domains: 1. Sociodemographic Variables Age, gender, socioeconomic status, education, occupation 2. Clinical Variables Type and duration of GI disorder Disease severity indices (validated scoring systems depending on disease) Comorbidities and medication history 3. Dietary Assessment Diet quality was assessed using a validated dietary assessment tool (e.g., Food Frequency Questionnaire or Diet Quality Index), evaluating: Macronutrient and micronutrient intake Consumption of fiber, fruits, vegetables Intake of processed and high-fat foods Adherence to healthy dietary patterns 4. Lifestyle Assessment Lifestyle factors were evaluated using standardized scales: Physical activity: International Physical Activity Questionnaire (IPAQ) Sleep quality: Pittsburgh Sleep Quality Index (PSQI) Stress levels: Perceived Stress Scale (PSS) Substance use: Smoking and alcohol consumption history 5. Outcome Measures Primary Outcome: Incidence and progression of gastrointestinal disorders Secondary Outcomes: Symptom severity scores Frequency of exacerbations Quality of life (GI-specific QoL tools) Exposure Definition Diet Quality: Categorized into low, moderate, and high based on composite dietary scores. Lifestyle Score: Composite index derived from physical activity, sleep, stress, and substance use parameters. Combined Exposure: Integrated diet–lifestyle score used to assess synergistic effects. Data Collection Procedure Eligible participants were recruited after obtaining informed consent. Baseline data were collected through direct interviews and clinical examination. Follow-up assessments were conducted periodically (e.g., 3, 6, and 12 months) to evaluate disease progression and changes in lifestyle and dietary patterns. Bias and Confounding Control Standardized and validated tools were used to minimize measurement bias Training of data collectors ensured uniform data acquisition Multivariable regression models were applied to adjust for confounders such as age, gender, and comorbidities Sensitivity analyses were performed to assess robustness of findings Statistical Analysis Data were entered into Microsoft Excel and analyzed using SPSS version 26 software.Descriptive statistics: Mean ± SD for continuous variables; frequency and percentage for categorical variables Inferential statistics: Chi-square test / Fisher’s exact test for categorical variables Independent t-test / ANOVA for continuous variables Multivariate analysis: o Logistic regression to assess associations between exposures and outcomes o Interaction analysis to evaluate synergistic effects of diet and lifestyle • Effect size and 95% confidence intervals were calculated • A p-value <0.05 was considered statistically significant Ethical Considerations The study protocol was reviewed and approved by the Institutional Ethics Committee (IEC) of Konaseema Institute of Medical Sciences and Research Foundation. Written informed consent was obtained from all participants prior to enrollment. The study adhered to the ethical principles outlined in the Declaration of Helsinki. STROBE Compliance This study was conducted and reported in accordance with the STROBE guidelines, ensuring transparency in study design, participant selection, variable definition, bias control, and statistical analysis.

Baseline Characteristics of Study Population A total of 124 participants were included in the final analysis. The mean age of the study population was 42.6 ± 13.8 years, with a slight male predominance (54.0% males, n=67). The majority of participants belonged to the 30–50 years age group (46.8%). Functional gastrointestinal disorders were more common than organic conditions, with irritable bowel syndrome (IBS) being the most prevalent diagnosis. Table 1: Sociodemographic and Clinical Characteristics (n = 124) Variable Category Frequency (n) Percentage (%) Age Group (years) 18–30 28 22.6 31–50 58 46.8 >50 38 30.6 Gender Male 67 54.0 Female 57 46.0 Type of GI Disorder IBS 40 32.3 GERD 32 25.8 IBD 18 14.5 Others 34 27.4 Duration of Illness <1 year 36 29.0 1–3 years 52 41.9 >3 years 36 29.0 Diet Quality and Lifestyle Characteristics Based on composite scoring, diet quality was categorized as low (34.7%), moderate (41.1%), and high (24.2%). Regarding lifestyle factors, a significant proportion of participants reported low physical activity (45.2%), poor sleep quality (39.5%), and moderate-to-high stress levels (48.4%). Table 2: Distribution of Diet Quality and Lifestyle Factors (n = 124) Variable Category Frequency (n) Percentage (%) Diet Quality Score Low 43 34.7 Moderate 51 41.1 High 30 24.2 Physical Activity Low 56 45.2 Moderate 42 33.9 High 26 21.0 Sleep Quality Good 75 60.5 Poor 49 39.5 Stress Level Low 28 22.6 Moderate 60 48.4 High 36 29.0 Smoking Status Yes 38 30.6 No 86 69.4 Alcohol Use Yes 41 33.1 No 83 66.9 Association Between Diet Quality and GI Disease Severity Patients with low diet quality had significantly higher disease severity scores compared to those with moderate and high diet quality (p < 0.01). A graded inverse relationship was observed between diet quality and symptom severity. Table 3: Association Between Diet Quality and Disease Severity Diet Quality Mild (n=38) Moderate (n=52) Severe (n=34) p-value Low (n=43) 8 (18.6%) 17 (39.5%) 18 (41.9%) <0.01 Moderate (n=51) 18 (35.3%) 25 (49.0%) 8 (15.7%) High (n=30) 12 (40.0%) 10 (33.3%) 8 (26.7%) Association Between Lifestyle Factors and GI Disease Outcomes Poor lifestyle scores (low physical activity, high stress, poor sleep) were significantly associated with increased disease severity and frequency of exacerbations (p < 0.05). Table 4: Association Between Lifestyle Score and Disease Severity Lifestyle Score Mild Moderate Severe p-value Healthy (n=35) 16 (45.7%) 14 (40.0%) 5 (14.3%) <0.05 Moderate (n=48) 14 (29.2%) 24 (50.0%) 10 (20.8%) Unhealthy (n=41) 8 (19.5%) 14 (34.1%) 19 (46.3%) Combined Effect of Diet and Lifestyle (Integrated Analysis) Participants with both poor diet quality and unhealthy lifestyle demonstrated the highest disease severity (52.4%) compared to those with either one or no risk factors. Multivariate logistic regression analysis revealed that: • Low diet quality (Adjusted OR: 2.8, 95% CI: 1.4–5.6) • Unhealthy lifestyle (Adjusted OR: 2.3, 95% CI: 1.2–4.5) • Combined exposure (Adjusted OR: 4.6, 95% CI: 2.1–9.8) were independently associated with severe gastrointestinal disease. Table 5: Multivariate Logistic Regression Analysis for Severe GI Disease Variable Adjusted OR 95% CI p-value Low Diet Quality 2.8 1.4–5.6 0.003 Unhealthy Lifestyle 2.3 1.2–4.5 0.01 Combined Exposure 4.6 2.1–9.8 <0.001 Variable Adjusted OR 95% CI p-value

The present study offers a multidimensional assessment of the combined influence of dietary quality and lifestyle-related factors on the severity and progression of gastrointestinal [GI] disorders. The findings indicate that both domains independently contribute to disease burden, while their concurrent presence exerts a stronger and synergistic adverse effect. Participants exposed to both poor dietary quality and unhealthy lifestyle factors had markedly greater odds of severe disease, underscoring the importance of evaluating modifiable risk factors in an integrated rather than isolated manner. A major finding of this study was the inverse association between diet quality and disease severity, suggesting that poorer dietary patterns are linked with worse gastrointestinal outcomes. Participants with better dietary scores showed lower symptom burden and fewer exacerbations, indicating a possible dose-response relationship. This observation is consistent with earlier studies highlighting the role of overall dietary patterns in gastrointestinal health rather than isolated nutrient effects [11,12]. Diets rich in fruits, vegetables, whole grains, fiber, and bioactive plant compounds are known to support microbial diversity and stimulate the production of short-chain fatty acids, which contribute to mucosal integrity and anti-inflammatory regulation within the gut [13]. Conversely, dietary patterns characterized by processed foods, high saturated fat content, and refined carbohydrates have been associated with dysbiosis, impaired intestinal barrier function, and activation of inflammatory pathways that may worsen disease progression [14]. The study also demonstrated the independent contribution of lifestyle-related factors, particularly physical inactivity, psychological stress, and poor sleep quality, to greater gastrointestinal disease severity. These findings reinforce the concept that GI disorders are shaped not only by biological and dietary factors but also by behavioral and psychosocial determinants. Chronic stress can activate neuroendocrine pathways, especially the hypothalamic-pituitary-adrenal axis, leading to changes in gut motility, secretion, mucosal defense, and visceral perception [15]. Such mechanisms are especially relevant in functional GI disorders, where stress-related symptom amplification is well recognized. In a similar manner, sleep disturbance has emerged as an important determinant of gastrointestinal health through its effect on circadian rhythm, inflammatory regulation, immune function, and gut microbial composition [16]. Disturbed sleep may therefore aggravate disease activity through multiple interrelated biological pathways. Physical activity appeared to exert a protective effect in the present study. Participants with moderate to high levels of activity had lower disease severity compared with those who were physically inactive. Regular exercise has been shown to improve gastrointestinal motility, reduce systemic inflammatory burden, and favorably influence the diversity and composition of the gut microbiota [17]. These observations support the inclusion of physical activity promotion within comprehensive management plans for patients with GI disorders. An important strength of the present study lies in its integrated analytical framework. While previous investigations have often evaluated diet and lifestyle variables separately, the current analysis demonstrates that their coexistence may produce an effect greater than the sum of their independent contributions. This suggests a multiplicative or synergistic interaction between these exposures. Such a finding has practical clinical relevance, because it implies that interventions targeting multiple modifiable behaviors simultaneously may be more effective than single-component strategies [18]. The use of a composite diet-lifestyle score further enhances the translational value of the study by reflecting more closely the clustering of real-world risk behaviors. These findings are particularly meaningful in the context of rapidly changing social and nutritional environments in developing regions. Urbanization, increased availability of processed foods, sedentary routines, irregular sleep, and rising psychosocial stress have collectively contributed to a growing burden of lifestyle-related GI disorders [19]. The present study reflects this evolving pattern and provides context-specific evidence that may be useful for planning preventive and therapeutic interventions in similar populations. Another relevant observation is the likely clustering of unhealthy behaviors. Poor diet often coexists with low physical activity, inadequate sleep, and heightened stress, and such clustering may amplify disease risk through shared pathways such as chronic inflammation, oxidative stress, autonomic imbalance, and neuroendocrine dysregulation. Recognition of this clustering is important because it argues against fragmented risk assessment and supports a broader behavioral model for GI disease prevention and care. Certain limitations should be acknowledged. The study relied partly on self-reported dietary and lifestyle data, which introduces the possibility of recall bias and reporting bias. Although validated instruments were used, some misclassification of exposure cannot be excluded. The single-center design limits the generalizability of the findings, and the observational design does not permit definitive conclusions regarding causality. In addition, residual confounding from unmeasured factors may still have influenced the observed associations. Future multicentric and longitudinal studies, along with intervention-based research incorporating objective biomarkers and microbiome-based approaches, would be valuable in clarifying the mechanisms underlying these observed relationships [20].

The present study demonstrates that diet quality and lifestyle-related behaviors are both independent and interacting determinants of gastrointestinal disease severity and progression. Poor dietary quality and unhealthy lifestyle practices were significantly associated with adverse gastrointestinal outcomes, and their combined presence produced a substantially greater effect than either factor alone. These findings highlight the importance of viewing gastrointestinal health through a multidimensional framework that recognizes the interplay of behavioral and nutritional determinants. The results support the adoption of integrated intervention strategies that combine dietary improvement with promotion of physical activity, stress reduction, and sleep optimization as part of routine gastrointestinal care. At the public health level, the study also emphasizes the need for preventive approaches addressing the broader lifestyle transition contributing to the increasing burden of GI disorders. Further research should focus on translating these findings into robust clinical protocols and evidence-based preventive models aimed at improving patient outcomes and reducing the long-term burden of gastrointestinal disease.

1. Collaborators GBD. Global burden of digestive diseases. Lancet Gastroenterol Hepatol. 2020;5(3):245–60. 2. World Health Organization. Global health estimates on digestive diseases. Geneva: WHO; 2021. 3. Mayer EA. Gut–brain axis in gastrointestinal disease. Nat Rev Gastroenterol Hepatol. 2019;16(8):453–67. 4. Lynch SV, Pedersen O. The human intestinal microbiome. N Engl J Med. 2016;375:2369–79. 5. Singh RK, et al. Influence of diet on gut microbiota. J Transl Med. 2017;15:73. 6. Statovci D, et al. Western diet and gut inflammation. Nutrients. 2017;9(7):E723. 7. Konturek PC, et al. Stress and the gut. J Physiol Pharmacol. 2011;62(6):591–9. 8. Reutrakul S, Van Cauter E. Sleep and gastrointestinal disorders. Sleep Med Rev. 2018;38:134–43. 9. Schwingshackl L, et al. Diet and lifestyle in chronic disease. BMJ. 2018;361:k2392. 10. Misra A, et al. Nutrition transition in India. Lancet Diabetes Endocrinol. 2019;7(6):478–90. 11. Schwingshackl L, et al. Diet quality and chronic disease risk. BMJ. 2018;361:k2392. 12. Mozaffarian D. Dietary patterns and health outcomes. Circulation. 2016;133(2):187–225. 13. Tilg H, Moschen AR. Gut microbiota and inflammation. Gut. 2014;63(9):1513–21. 14. Zinöcker MK, Lindseth IA. Western diet and gut dysbiosis. Nutrients. 2018;10(3):365. 15. Konturek PC, et al. Stress and gut physiology. J Physiol Pharmacol. 2011;62(6):591–9. 16. Reutrakul S, Van Cauter E. Sleep and GI disorders. Sleep Med Rev. 2018;38:134–43. 17. Pedersen BK, Saltin B. Exercise and inflammation. Scand J Med Sci Sports. 2015;25(S3):1–72. 18. Khanna S, Tosh PK. Microbiome in GI disease. Mayo Clin Proc. 2014;89(1):107–14. 19. Misra A, et al. Nutrition transition in India. Lancet Diabetes Endocrinol. 2019;7(6):478–90. 20. Rothman KJ. Modern epidemiology. Lippincott Williams & Wilkins; 2012.