Demographic transition in health and nutrition

Question 1

Country income groups

Answer 1

Economies are currently divided into four income groupings by the World Bank: low, lower-middle, upper-middle, and high, based on GNI per capita.

For the current 2022 fiscal year,
low-income economies are defined as those with a GNI per capita, of $1,045 or less in 2020;
lower middle-income economies are those with a GNI per capita between $1,046 and $4,095;
upper middle-income economies are those with a GNI per capita between $4,096 and $12,695;
high-income economies are those with a GNI per capita of $12,696 or more.

Question 2

demographic ‘megatrends

Answer 2

The UN has highlighted four demographic megatrends, each of which holds important implications for economic and social development and for environmental sustainability (UN, 2019):

Population growth

Population ageing

Migration

Urbanisation

Question 3

population growth and ageing (UN, 2022)

Answer 3

Latest UN projections: global population of 8.5 billion in 2030, 9.7 billion in 2050, 10.4 billion peak in 2080s

↑ life expectancy (average 72.8 in 2019) and ↓fertility rate (2.3), reduced growth rate

Projected population growth is uneven and the least developed countries are among the fastest growing – pressure on schooling and healthcare and impact on achieving SDG targets

% of global population over 65 years is projected to rise from 10% in 2022 to 16% in 2050 – consideration for social security, pension and health coverage

Migration expected to be the sole driver of population growth in high income countries

Question 4

An alternative population forecast from GBD study (Vollset et al., 2020)

positive + negative impacts

Answer 4

Based on estimates of mortality, fertility and migration, depending on scenarios based on education provision, reproductive health etc.

Prediction differs from UN – world population to peak at 9.73 billion in 2064 (95% UI 8.84-10.9) and decline to 8.79 billion in 2100 (95% UI 6.83-11.8)

Potential impact:
Potentially positive impact for environment, climate change and food production

Potentially negative impacts for labour forces, economic growth and social support where decline in fertility is greatest

Some HICs with fertility rate below replacement rate will need to maintain working age population through liberal immigration policies plus policies to increase fertility rate?

Question 5

urbanisation (UN, 2018)

Answer 5

Urbanization is a complex socio-economic process that transforms the built environment, converting formerly rural into urban settlements, while also shifting the spatial distribution of a population from rural to urban areas. It includes changes in dominant occupations, lifestyle, culture and behaviour, and thus alters the demographic and social structure of both urban and rural areas.

Globally, the percentage of people living in urban areas is increasing:
30% in 1950, 55% in 2018, Predicted 68% by 2050

Wide variation between countries and regions:
Northern America: 82% urban, Africa: 43% urban

Faster population growth projected in urban areas – therefore it is important that this promotes health and wellbeing

Question 6

Positive Impacts of urbanisation on health (Eckert & Kohler, 2014)

Answer 6

Access to employment

Access to education and healthcare

Social interaction

Cultural opportunities

Opportunities for physical activity - green spaces/cycle lanes

Question 7

Negative Impacts of urbanisation on health (Eckert & Kohler, 2014)

Answer 7

Air pollution - respiratory/CVD disease

Slum housing/overcrowding

Lack of infrastructure - can the health service cope?

High rise housing limiting social interaction

Increased noise

Increased violence

Increased traffic

Risk of infectious disease

Dietary impact– trends to ↑ refined grains, foods higher in fat, animal products, sugar, processed foods, food from out of home, ↓ breastfeeding

Question 8

Leading global causes of death (WHO, 2020)
C, N-C, I

Answer 8

Causes of death grouped into 3 categories:

• communicable (infectious and parasitic diseases, maternal, perinatal and nutritional conditions)
• non-communicable (stroke, cancer, lunch disease)
• injuries

Globally, 7/10 leading causes of death were non-communicable

NCDs were responsible for 74% global deaths in 2019

Since 2000, ↑ non-communicable and ↓ communicable causes

Question 9

Leading causes of death in Low income countries (WHO, 2020)

Answer 9

More likely to die from communicable disease than NCD (6/10 leading causes)

Malaria, TB and HIV/AIDS in top 10, but fallen significantly since 2000

Diarrhoeal disease in top 5 causes of death, but fallen significantly since 2000

Since 2000, falls in all communicable causes, and increases in non-communicable

Question 10

Leading causes of death in high income countries (WHO, 2020)

Answer 10

9/10 leading causes of death are non-communicable

Since 2000, falls in number of deaths from IHD and stroke

Since 2000, increase in deaths from dementia (and other causes)

Only one communicable cause of death in the top 10 – lower respiratory infections (e.g. pneumonia)

Question 11

changing health risks with economic development

basic needs

Answer 11

‘Traditional’ risks and public health challenges:

Sanitation
Housing
Drinking water
Education
Employment
Working conditions
Safe food supply

Question 12

Demographic and epidemiological transitions (popkin, 1993; popkin, 2008)

Answer 12

Demographic transition – shift from pattern of high fertility & high mortality to low fertility & low mortality (typical of high income countries)

Epidemiologic transition – shift from pattern of high prevalence of infectious disease and malnutrition with periodic famine and poor sanitation to pattern of high prevalence of chronic and degenerative diseases associated with ‘lifestyle’. Accompanied by major shift in age-specific mortality patterns and consequent increase in life expectancy.

Concurrent changes also occur in the composition of diet –the nutrition transition -reflected in nutritional outcomes (e.g. stature, body composition) – converging on a dietary pattern high in saturated fat, sugar and refined foods and low in fibre (‘Western diet’).

Understanding this process could help to define policy changes to ‘redirect’ nutrition transitions in lower income countries

Question 13

Nutrition transition (popkin, 1993; popkin, 2008)
5 PATTERNS

Answer 13

Five broad patterns in structure/composition of overall diet reflected in nutritional outcome:

1. Collecting food
2. Famine
3. Receding famine
4. Degenerative diseases
5. Behavioural change

Question 14

drivers of the nutrition transition (Popkin, 2015)

what is changing peoples diets?

Answer 14

Critical underlying drivers:

Technology: labour saving for work & home, transport, sedentary leisure activities

Urbanisation: access to wider range of food, ↑food processing, ↑consumption of food produced by others

Shift in per capita income: ↓price of food in hours of work/kcal

Expansion of global trade in services: access to modern technology and manufacturing

Major direct drivers:

Physical activity: declining rapidly, particularly in LMICs
Concurrent shifts in diet to converge on ‘Western diet’ pattern particularly in urban areas

↑ vegetable oil consumption

Sweeter diet, ↑ SSBs

↑ animal source foods

Refined carbohydrates replacing legumes, grains and other veg.

Question 15

Economic development and obesity (LOBSTEIN & leach, 2007)

Answer 15

Linear, positive relationship between GDP and mean BMI up to GDP of $5000, which then flattens

In LMICs, groups of high socioeconomic status in urban areas tend to be first to have high obesity prevalence, with burden shifting to low SES groups and rural areas as GDP increases further

Question 16

Variation in nutrition transition (popkin, 1993; popkin, 2008)

Answer 16

Process seen in high income countries will not necessarily be replicated across the world – nature and pace related to:

Major shifts in population growth, age structure and spatial distribution are closely associated with nutritional trends/dietary change (declines in fertility, ageing populations, urbanisation, migration)

Role of the food industry/government in determining the diet during socioeconomic development (e.g. processing, preservation, availability of infant formula)

Changes in socioeconomic structure leading to changes in women’s roles and shifts in dietary patterns (↑ income associated with ↑animal fat and protein, sugar ↓vegetable fat and protein, carbohydrate)

Dietary change is associated with changes in the public’s knowledge about role of diet in health

Interaction between epidemiological, socioeconomic and demographic changes determines the nature and pace of nutritional transition

Question 17

double burden of malnutrition (DBM)
(popkin, corvalan & grummer-strawn, 2020; wells et al., 2020)

Answer 17

The simultaneous manifestation of both undernutrition (micronutrient deficiencies, underweight, childhood stunting and wasting) and overweight, obesity and non-communicable diseases affecting many LMICs (particularly S/E Asia, Sub-Saharan Africa) due to face of change:

• seen at country, household and individual level
• New nutrition reality: ‘multiple forms of malnutrition that overlap in different ways and in different places’

‘Obesogenic environments expanding, while the causes of undernutrition persist’’

Many causes related to stage of nutrition transition dominated by increased access to less healthy, highly processed foods and beverages and reduced physical activity (work, home, transportation)

• key drivers = urbanisation, migration to cities, income growth, global trade liberalisation, changes in women at work, marketing and media
• life course exposure to DBM in individuals (fetal/infant undernutrition followed by adult overnutrition) increases risk of non-communicable diseases

Question 18

Nutrition transition & related health challenges in china (huang et al., 2021)

Answer 18

Review of long-term dietary trends (1982-2012) using national nutrition and health survey data during period of rapid and continuous economic transition, accompanied by ageing population, rapid urbanisation and industrialisation.

Significant changes in dietary structure of Chinese adults from traditional diet pattern (cereals, vegetables, few animal foods) to more Western patten:
- ↓ cereals, vegetables
- ↑ animal foods (pork), processed foods, SSBs
- ↔ eggs, fish, dairy
- high use of cooking oil, salt

Lifestyle and working conditions greatly improved over this period, with shift to more sedentary occupations and more technologies and electronic ownership (reduction in outdoor activities)

Duel challenges of under and overnutrition in China:
- Reduction in underweight and anaemia prevalence
- Continuing high ‘hidden hunger’ (e.g. micronutrient deficiency)
- Rapid increase in adult obesity prevalence (16.4% in 1982 to 30.1% in 2012)
- Increasing prevalence of hypertension, diabetes and CVD

Question 19

Addressing malnutrition in all forms (hawkes et al., 2020)

Answer 19

‘double duty interventions’ acting on common drivers
- early life nutrition
- diet diversity
- food environments
- socioeconomic factors)

Proposed candidates for double-duty action:
- Health services: antenatal care, promote and support breastfeeding, complementary feeding, growth monitoring, prevent harm from supplements

• Social safety nets: redesign cash subsidies, vouchers
• Educational settings: school feeding programmes
• Agriculture, food systems, food environments: agricultural programmes, food systems to support healthy diets, improve food environments

Question 20

Global policy – 2025 global nutrition targets

Answer 20

The 2021 Global Nutrition Report reports that the word is off course to meet five of the six maternal, infant and young child nutrition targets, and all of the diet-related NCD voluntary targets

Question 21

Global policy – sustainable development goals

Answer 21

17 Global goals for sustainable development 2015-2030, encompassing 3 dimensions of sustainable development: economic growth, social inclusion and environmental protection

Includes goals related to health, wellbeing and nutrition, including:
- 2.2By 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, and address the nutritional needs of adolescent girls, pregnant and lactating women and older persons.
- 3.4By 2030, reduce by one third premature mortality from non-communicable diseases through prevention and treatment and promote mental health and well-being.

Question 22

ongoing nutrition transition (Bodirsky et al., 2020)

Answer 22

Modelling of continued global nutrition transition to 2050 concluded current trends not in line with achieving relevant SDGs:

• 45% world’s population overweight and 16% obese (2010 = 29% and 9% respectively)
• Prevalence of underweight halves, but absolute numbers stagnate at 0.4-0.7 billion people
• Dietary consumption shifts towards animal sourced foods and empty calories, insufficient increases in veg, fruit and nuts
• Global food demand increases due to population growth, ageing, increasing body mass
• ‘Achieving zero hunger, healthy diets, and food demand compatible with environmental boundaries necessitates a coordinated redirection of the nutrition transition’
• Greatest benefit in reducing multiple symptoms – substituting animal source foods and reducing household waste