Health effects of Climate ChangeInitiatives in Bangladesh

Paolo Vineis

Aneire Khan

Imperial College London

Which strategy in low-income, high-risk countries?

Capacity building:

- improvement of health statistics, hospital records, hospital discharge data …- use of remote sensing data and GIS to assess “exposures” (eg frequency of

floods, drought, changes in vegetation and agricultural practices, spreading of vectors) …

- need for good epidemiological studies with formal design- proposals and training for adaptation and mitigation

Climate & health effects in Bangladesh

• Bangladesh is vulnerable to natural hazards and the future effects of climate change.

– Deltaic plains of the Ganges, Brahmaputra Meghna rivers

– Suffer from acute climate events – floods, droughts, cyclones

– Long-term environmental degradation → salinization & soil degradation

– Effects likely to be exacerbated by climate change & sea-level rise

Research questions

• Feasibility study that will provide the necessary tools to address the following questions:

1. What are the health effects of environmental salinization?

2. Do climate-induced events (e.g. floods and droughts) affect micronutrient intake in rural populations?

Specific goals:

• Measure variation in solute composition in drinking water sources in coastal villages, develop protocols for measuring urinary salt excretion in order to design a cross-sectional study on hypertension and CVD risk.

• Perform exploratory hospital-based case-control study on association between water source & (pre)clampsia among pregnant women in the same area

• Define a set of markers of micronutrient intake that can be used assess health impacts of floods in rural Bangladeshi women

Map showing different SLR scenarios to estimate how much salt water will intrude inland

• Rising sea levels in the Bay of Bengal encroaching inland in the southern districts of Bangladesh - resulting in salinization

• Currently saline 2.8 million ha

• 20 million people currently affected by varying degrees

• In the last 50 years, salinity has risen by 45%

CLIMATE CHANGE

Rainfall,Monsoon

Snowmelt

Sea-level rise

Runoff

River flow

Estuarine intrusion

Saltwater intrusion [shallow

groundwater]

Surface water salinity

[downstream][river]

Shrimp farmingPoor land

management

Pond water[consumption]

Healtheffects

Simplified causal diagram of salinity & health

% prevalence of hypertensive disorders in women attending antenatal check-ups [May – July 2007]

0

2

4

6

8

10

12

14

16

Dacope Terokhada Matwail

preeclampsia

eclampsia

hypertension

Choice of study area for salinity study

• Shyamnagar, a sub-district in Satkhira: – Cross sectional study of water sources, their salinity and urinary

salt concentrations in a range of coastal villages• Dacope, a sub-district in Khulna:

– Case control study: Higher rates of (pre)clampsia among pregnant women are associated with consumption of saline drinking water at home

• Baseline survey in 3 villages in Shyamnagar: 61% of households used pond water for drinking and 81% used it for household purposes in the dry season.

• Access to tube wells was extremely limited and NGOs are currently supporting rainwater harvesting intervention.

Rainfall, flooding and droughts• More than 80% of the 2,300 mm of annual precipitation in Bangladesh occurs during

the monsoon period • A quarter of the country is currently flood-prone in a normal hydrological year, which

may increase up to 39% under climate change scenarios in the next century.

• Predictions: – episodes of heavy rainfall and drought are likely to become more frequent and

severe – increased frequency and severity of hot spells & heavy precipitation events are

expected to have negative impacts on crop yield and areas of cultivatable land

Historical flood extents in Bangladesh [OECD 2003]

Most of Bangladesh at high risk from flooding, sea-level rise, and

stronger storms

Floods

Injuries

Population displacement

Adverse effects on food production

Freshwater availability and quality

Increased risk of infectious diseases - diarrhoeal diseases

Toxic contamination

Mental health

• Higher rates of stunting and wasting among flood exposed pre-school children and higher rates of chronic energy deficiency among flood exposed women (Del Ninno 2001).

Acute and chronic nutritional problems

- undernutrition, protein-energy malnutrition, micro-nutrient deficiency

Infectious diseases Respiratory diseases Deaths Production of wheat and rice might no longer

be economically suitable under climate change.

Protein-energy and micronutrient-related malnutrition have been reported in children in post flood affected areas (ICDDR,B).

A study found that drought, lack of food were associated with increased risk of mortality from diarrhoeal diseases (Aziz 1991)

Low precipitation: drought

Floods, drought & micronutrient deficiency

• A large segment of population in South Asian region including Bangladesh suffer from micronutrient deficiencies

• Usually occurs in frequently flooded, low-lying areas where, over time, micronutrients have been washed out of the soil

• Reflected in Bangladeshi soils: low level of certain minerals in rice, vegetables, and staples of the rural and poor Bangladeshi diet

• Severe micronutrient deficiency in women, a common problem in rural Bangladesh, increases the risk of bearing children with low birth weight, and other health problems.

• Short and longer term impacts of flooding on micronutrient deficiency have not been well researched.

The impact on women

• Women suffer disproportionately more during disasters

– 70% of world’s poor are women– Women account for the majority of

climate-related deaths

Biological vulnerabilities: – Nutrition– Reproductive health

Social vulnerabilities: – Poverty– Discrimination– Stigma– Sexual violence

• Need for international climate policies to be gender aware

Choice of study area for a micronutrient study

• HEALS cohort (Columbia University & Bangladesh)– Rural sub-district, Araihazar.

• Significantly affected by river floods in 2004, 2005 and 2007, while regular yearly monsoon rainfall and flooding affect inhabitants in areas of flat land.

• Population-based cohort: 20,000 participants between 18 - 75 years of age • A full questionnaire interview including validated FFQ filled at baseline

(2000-2002).

This cohort provides an ideal setting to conduct a pilot study to investigate changes in micro-nutrients intake of rural women attributable to climate variability.

• Compare nutritional indices in the dry season and after monsoon floods using data collected among the 200 participants (100 from villages of flat land; 100 from areas of higher land surface), and carry out multivariate analysis, adjusting for potential confounders

Given the uncertainties on the extent of micronutrient deficiency → this component is a pilot study to assess the frequency of deficiencies in two areas with different likelihood of floods.

The purpose is to contribute to the design of proper studies on nutritional impacts of flooding and drought in the HEALS cohort.

Capacity Building• The study will support research capacity in

Bangladesh, building upon existing facilities and experiences (BCAS, HEALS, KMC).

• Experience from HEALS will be used to develop research tools and transfer of expertise to other study areas.

• Training of nurses and interviewers to build an

infrastructure that can be used in future well-designed studies on climate change effects in Bangladesh.

• Training local scientists to monitor salinity in drinking water

• Disseminate our research findings and foster discussion among local community health representatives, local political bodies, &collaborators, for developing awareness & adaptation strategies