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by Dr PHUA Kai Lit
School of Medicine and Health Sciences
Monash University Sunway Campus
Bandar Sunway, Malaysia

What is Migration?

Movements of people within a country (internal migration) or across national boundaries (international migration).
It can be voluntary or involuntary. It can also be temporary or permanent.

1. Issues Related to Migration

Who migrates?
When do they migrate i.e. how old are they when they migrate?
Where do they migrate from (place of origin)?
Where do they migrate to (place of destination)?
Why did they migrate?

Is the migration temporary (i.e. is there "return migration" to the place of origin) OR is it permanent?

1a. Who Migrates
Migrants tend to be younger and healthier than non-migrants (those who stay behind).
Often, they are also better-educated than non-migrants. In the past, migrants tended to be male.
Nowadays, many migrants are women.

1b. When Did They Migrate (Age at Migration)
If people migrate when they are very young,
they will adopt the customs and behaviour (including health-related behaviour such as diet) of the new place more readily.

If people migrate when they are already adults,
they will retain more of the customs and behaviour (including health-related behaviour such as diet) of the old place (place of origin).

1c. Where Did They Come From and Where Do They Go?
Internal Migration
a. Rural to urban area within one country (and vice-versa)
b. Urban area to suburban area within one country
c. Other combinations e.g. small urban area to large urban area

International Migration
a. Place of origin and place of destination are in different countries
b. Migration may be from Country A to Country C (with Country B as an intermediate stop)

Did migrants move from a high-risk area (in terms of health hazards) to a low-risk area? Or from a low-risk area to a high risk-area?

What are the negative effects of the new area e.g. inner city slums in rich countries?

How much of the healthy customs and behaviour of their place of origin did they retain ("protective effect")?
How much of the healthy customs and behaviour of the new area did they adopt?
Did the process of migration negatively affect their health?

1d. Why Did They Migrate?
Labour migration: skilled versus unskilled, legal versus illegal
Return migration e.g. retirement, sick returnees

2. How is Migration Related to Health?
a. Health conditions at place of origin
b. Did process of migration affect health?
c. Health conditions at place of destination

Since migrants tend to be younger and healthier, there is the so-called
"healthy migrant" effect. This makes it harder to measure the actual impact of the new environment on the health of immigrants.

There may be "convergence" in health status between descendants of the immigrants and the locals after many years.

3. Categories of Migrants and Their Health
Labour migrants:
Exploitation of migrant workers (especially the unskilled and illegal ones)
STDs and HIV/AIDS in male migrant workers e.g. mine workers in Southern Africa who periodically migrate from their villages in
Mozambique to work in mines in South Africa, trucks drivers who spread STDs and HIV/AIDS along trucking routes
(and who also spread STDs and HIV/AIDS to their wives and girlfriends when they get home)
Import of diseases i.e. when people move from less healthy countries to more healthy countries
(such as immigrant workers who come into Malaysia with TB, filariasis, leprosy etc)

War, "ethnic cleansing", natural disasters, famines, etc.
Conditions in refugee camps i.e. food availability, clean water,
sanitation, clothing, protection from bad weather, protection from vectors
of disease, safety from inter-personal violence in the camps

Resettlement (voluntary):
Long term adjustment problems of immigrants. (Especially peasants who move from Country A
to inner city areas in Country B which has a very different culture/values).

Tourists (next lecture!)

e.g. retirees and sick returnees
These will drive up demand for health and health-related social services