Geospatial analysis of diarrheal disease burden and associated health determinants among under-five children in Karnataka using NFHS data – Nature

Report on the Spatio-Temporal Distribution of Childhood Diarrhoeal Disease in Karnataka and its Implications for Sustainable Development Goals

Executive Summary

Diarrhoeal disease remains a significant barrier to achieving Sustainable Development Goal 3 (Good Health and Well-being), particularly Target 3.2, which aims to end preventable deaths of children under five. This report presents a spatio-temporal analysis of diarrhoeal disease prevalence among children under five in Karnataka, India, using district-level data from the National Family Health Survey (NFHS-4: 2015–16 and NFHS-5: 2019–21). The analysis reveals considerable geographic heterogeneity and evolving disease patterns, highlighting the critical interplay between child health (SDG 3), nutrition (SDG 2), and access to clean water and sanitation (SDG 6). Key findings indicate the emergence of new disease hotspots in northern districts and a persistent spatial co-clustering of diarrhoea and child undernutrition. These insights underscore the necessity of localized, data-driven public health strategies to accelerate progress towards the 2030 Agenda for Sustainable Development by identifying and targeting high-burden districts with integrated interventions.

1.0 Introduction: Aligning with Sustainable Development Goals

The 2030 Agenda for Sustainable Development provides a global framework for promoting health and well-being for all. Diarrhoeal disease, a leading cause of under-five morbidity and mortality, directly impedes progress on several interconnected Sustainable Development Goals (SDGs).

• SDG 3 (Good Health and Well-being): The global target to reduce under-five mortality to fewer than 25 deaths per 1,000 live births (Target 3.2) cannot be met without addressing preventable illnesses like diarrhoea.
• SDG 2 (Zero Hunger): The vicious cycle of diarrhoea and malnutrition undermines efforts to end all forms of malnutrition (Target 2.2), as recurrent infections impair nutrient absorption and weaken immunity.
• SDG 6 (Clean Water and Sanitation): The primary drivers of diarrhoeal disease—contaminated water, inadequate sanitation, and poor hygiene—are central to SDG 6, which calls for universal access to clean water and sanitation (Targets 6.1 and 6.2).

In India, national initiatives such as the Swachh Bharat Abhiyan (Clean India Mission), Jal Jeevan Mission (Water is Life Mission), and POSHAN Abhiyaan (National Nutrition Mission) are designed to address these determinants. However, their impact varies significantly at the subnational level. This report investigates the spatial and temporal dynamics of childhood diarrhoea in Karnataka to provide evidence for geographically targeted interventions that can accelerate the achievement of these critical SDGs.

2.0 Methodology for SDG-Focused Geospatial Analysis

2.1 Data and Study Population

This cross-sectional analysis utilized district-level data for children under five from two rounds of the National Family Health Survey (NFHS) in Karnataka:

1. NFHS-4 (2015–16): Surveyed 7,443 children.
2. NFHS-5 (2019–21): Surveyed 8,140 children.

The NFHS employs a multistage stratified sampling design, ensuring data is representative at the district level, which serves as the primary unit for public health implementation in India.

2.2 Key Variables and their Relation to SDGs

The analysis focused on the following variables, which serve as indicators for specific SDG targets:

• Dependent Variable: Prevalence of diarrhoea among children under five (Indicator for SDG 3.2).
• Independent Variables (Determinants):
  • Percentage of households with improved sanitation facilities (Indicator for SDG 6.2).
  • Percentage of households with improved drinking water sources (Indicator for SDG 6.1).
  • Percentage of children underweight, stunted, or wasted (Indicators for SDG 2.2).
  • Percentage of children with an adequate diet (Indicator for SDG 2.2).

2.3 Statistical Analysis

Geospatial statistical methods were employed to identify spatial patterns and inequalities (relevant to SDG 10: Reduced Inequalities).

1. Global Moran’s I: To assess overall spatial autocorrelation of diarrhoeal disease prevalence.
2. Local Indicators of Spatial Association (LISA): To identify statistically significant spatial clusters (hotspots and cold spots) of high or low disease prevalence.
3. Bivariate LISA: To analyze the spatial co-clustering between diarrhoea prevalence and its key determinants related to SDG 2 and SDG 6.

3.0 Spatio-Temporal Analysis of Diarrhoeal Disease and SDG Determinants

3.1 Geographical Distribution and Progress Towards SDG 3.2

The analysis revealed significant spatial and temporal shifts in diarrhoeal disease prevalence between NFHS-4 and NFHS-5, indicating uneven progress towards SDG 3.2 across Karnataka.

• Persistent High-Burden Areas: Gadag district consistently recorded the highest prevalence in both surveys (9.5% in NFHS-4 and 10.4% in NFHS-5), signifying an entrenched challenge to child health goals.
• Emerging Hotspots: Northern districts showed a worrying increase in prevalence, threatening to reverse progress. Notable increases were observed in:
  • Bidar (from 3.3% to 9.0%)
  • Kalaburagi (from 0.9% to 9.4%)
• Areas of Improvement: Southern districts demonstrated significant reductions, suggesting successful public health interventions. These include:
  • Mysuru (from 7.7% to 3.0%)
  • Chikkamagaluru (from 8.9% to 4.8%)

3.2 Spatial Clustering and Hotspot Identification

Univariate LISA analysis identified a shift in the geographic concentration of the disease burden.

• NFHS-4: A significant high-high cluster (hotspot) was identified in Shivamogga, while low-low clusters (cold spots) were found in the northern districts of Bidar, Yadgir, and Vijayapura.
• NFHS-5: The strong clustering observed in NFHS-4 dissipated. No significant high-high or low-low clusters were found, indicating a more diffuse spatial pattern. However, several low-high clusters emerged in northern districts, suggesting that some areas improved while their neighbours worsened, creating sharp spatial disparities.

3.3 Bivariate Analysis: Linking Diarrhoea to SDG 2 and SDG 6

Bivariate spatial analysis revealed evolving relationships between diarrhoea and its key determinants.

• Sanitation (SDG 6.2): The spatial association shifted over time. In NFHS-5, a negative spatial correlation emerged in northern districts (Bidar, Kalaburagi), where high diarrhoea prevalence co-located with poor sanitation access. This reinforces the critical role of sanitation infrastructure in achieving SDG 3.
• Nutrition (SDG 2.2): A strong and consistent spatial co-clustering was observed between high diarrhoea prevalence and high rates of underweight children in both survey rounds. This highlights the persistent malnutrition-infection cycle as a major barrier to achieving both SDG 2 and SDG 3.
• Drinking Water (SDG 6.1): The spatial association between access to improved drinking water and diarrhoea prevalence was inconsistent across both surveys. This suggests that infrastructure access alone is insufficient and must be complemented by measures ensuring water quality and safe hygiene practices to meet SDG 6 targets.

4.0 Discussion: Implications for Achieving the 2030 Agenda

The findings underscore the profound intra-state heterogeneity in childhood diarrhoea, posing a significant challenge to SDG 10 (Reduced Inequalities). The emergence of new hotspots in northern Karnataka suggests that the benefits of state and national health programs are not reaching all districts equitably. The persistent spatial link between diarrhoea and undernutrition confirms that progress on SDG 3 is inextricably linked to progress on SDG 2. Integrated strategies that combine WASH (Water, Sanitation, and Hygiene), nutrition, and maternal-child health interventions are essential.

The inconsistent relationship with drinking water access highlights that achieving SDG 6 requires more than infrastructure; it necessitates a focus on water safety, household water treatment, and hygiene promotion. The dissipation of clear spatial clusters from NFHS-4 to NFHS-5 indicates a more complex and unpredictable disease landscape, demanding enhanced, district-level surveillance systems to guide public health responses effectively.

5.0 Conclusion and Strategic Recommendations for SDG Acceleration

Childhood diarrhoea remains a formidable obstacle to achieving the health-related SDGs in Karnataka. The identification of spatial hotspots and their associated determinants provides a clear roadmap for targeted action.

Recommendations:

1. Adopt Targeted, District-Specific Strategies: Move away from uniform statewide approaches and focus resources on identified high-burden districts and emerging hotspots, particularly in northern Karnataka.
2. Strengthen Integrated Service Delivery: Implement multisectoral interventions that simultaneously address sanitation and hygiene (SDG 6), child nutrition (SDG 2), and primary healthcare services (SDG 3) in vulnerable regions.
3. Enhance Geospatial Surveillance: Integrate spatial intelligence into public health planning to monitor disease trends, optimize resource allocation, and track progress towards SDG targets at a granular level.
4. Promote Behavioral Change: Complement infrastructure development (SDG 6) with culturally appropriate awareness campaigns on hygiene practices and the importance of nutrition to break the malnutrition-infection cycle (SDG 2).

By leveraging geospatial analysis to guide policy and practice, Karnataka can more effectively reduce the burden of diarrhoeal disease and accelerate its progress towards achieving the Sustainable Development Goals for all its children.

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The article on diarrhoeal disease among children under five in Karnataka, India, directly addresses and connects to several Sustainable Development Goals (SDGs). The primary focus on child health, its determinants like nutrition, and environmental factors such as water and sanitation, links the research to the following SDGs:

• SDG 3: Good Health and Well-being

  This is the most central SDG in the article. The entire study revolves around understanding and reducing “under-five morbidity and mortality” from diarrhoeal disease. The introduction explicitly states that progress in reducing childhood diarrhoeal mortality has not been “rapid or equitable enough to meet Sustainable Development Goal (SDG) targets” and later mentions the relevance of the study “in the context of India’s ongoing efforts to achieve SDG-3 and reduce child mortality.”

• SDG 2: Zero Hunger

  The article establishes a strong link between nutritional status and diarrhoeal disease. It investigates determinants such as “undernutrition,” “dietary adequacy,” “underweight, stunting, and wasting.” The discussion highlights the “malnutrition–infection cycle,” where repeated infections like diarrhoea worsen undernutrition. This directly connects to the goal of ending all forms of malnutrition.

• SDG 6: Clean Water and Sanitation

  The article identifies inadequate water, sanitation, and hygiene (WASH) as primary causes of diarrhoea. It states that diarrhoeal diseases are “predominantly transmitted through contaminated food, unsafe water, or inadequate sanitation and hygiene practices.” The analysis assesses the spatial association between diarrhoea and “sanitation coverage” and “access to improved drinking water.” Furthermore, it mentions national initiatives like “Swachh Bharat Abhiyan” (Clean India Mission) and “Jal Jeevan Mission” (Water Life Mission), which are directly aimed at improving sanitation and water access, respectively.

2. What specific targets under those SDGs can be identified based on the article’s content?

Based on the specific issues discussed, the following SDG targets can be clearly identified:

1. Under SDG 3 (Good Health and Well-being):

   • Target 3.2: By 2030, end preventable deaths of newborns and children under 5 years of age. The article directly references this target by stating, “Achieving the global goal of reducing under-five mortality to fewer than 25 deaths per 1000 live births by 2030 necessitates intensified, geographically targeted, and evidence-based interventions.” The study’s focus on a leading cause of under-five mortality (diarrhoea) is entirely aligned with this target.
   • Target 3.3: By 2030, end the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases. Diarrhoeal disease is a major water-borne and communicable disease. The article’s investigation into its prevalence, causes (like “contaminated food, unsafe water”), and spatial distribution is aimed at combating this type of disease.
   • Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination. The article’s focus on diarrhoea transmitted through “unsafe water” directly relates to reducing illnesses from water contamination.

2. Under SDG 2 (Zero Hunger):

   • Target 2.2: By 2030, end all forms of malnutrition, including achieving, by 2025, the internationally agreed targets on stunting and wasting in children under 5 years of age. The article analyzes the spatial association between diarrhoea and “anthropometric indicators of child undernutrition (underweight, stunting, and wasting).” It finds a “persistent overlap between undernutrition and high DD prevalence,” directly addressing the challenge of malnutrition.

3. Under SDG 6 (Clean Water and Sanitation):

   • Target 6.1: By 2030, achieve universal and equitable access to safe and affordable drinking water for all. The study uses “access to improved drinking water” as a key variable and discusses the impact of programs like the “Jal Jeevan Mission,” which aims to provide safe drinking water.
   • Target 6.2: By 2030, achieve access to adequate and equitable sanitation and hygiene for all and end open defecation. The article investigates “sanitation coverage” as a critical determinant of diarrhoea prevalence and mentions the “Swachh Bharat Abhiyan,” a national campaign focused on improving sanitation and ending open defecation.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article explicitly mentions and uses several indicators drawn from the National Family Health Survey (NFHS) data, which can be used to measure progress towards the identified SDG targets.

• Indicators for SDG 3 (Good Health and Well-being):

  • Under-five mortality rate (Indicator 3.2.1): While the article doesn’t provide the rate itself, it repeatedly refers to “under-five mortality” as the primary outcome of concern and mentions the global target of “fewer than 25 deaths per 1000 live births.”
  • Prevalence of diarrhoea: The study’s main dependent variable is the “prevalence of diarrhoea among children under 5 years of age,” measured as the percentage of children who experienced it in the two weeks preceding the survey. This serves as a direct measure of morbidity from a key water-borne disease (relevant to Target 3.3).

• Indicators for SDG 2 (Zero Hunger):

  • Prevalence of stunting (Indicator 2.2.1): The article uses the “percentages of children who are stunted” as an independent variable to assess its spatial association with diarrhoea.
  • Prevalence of wasting (Indicator 2.2.1): Similarly, the “percentages of children who are… wasted” is used as a key indicator of acute malnutrition.
  • Prevalence of underweight: The study analyzes the “percentages of children who are… underweight” and finds a “consistent spatial co-clustering” between diarrhoea and underweight prevalence.
  • Dietary Adequacy: The article analyzes the spatial association between “adequate diet” and diarrhoea prevalence, which is a measure of nutritional intake.

• Indicators for SDG 6 (Clean Water and Sanitation):

  • Proportion of population using safely managed drinking water services (Indicator 6.1.1): The article uses a proxy for this by measuring the “percentage of households with… access to drinking water sources.”
  • Proportion of population using safely managed sanitation services (Indicator 6.2.1): The study measures this through the “percentage of households with access to improved sanitation facilities.”

4. Create a table with three columns titled ‘SDGs, Targets and Indicators” to present the findings from analyzing the article.

Source: nature.com