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Worldwide, based on the available prevalence studies, there are likely to
be more than 6 million people with Parkinson's
Disease.
However, due
to so many people with Parkinson's Disease remaining undiagnosed, there
may be millions more. In China alone there are more than 1.7 million
people with Parkinson's Disease.
WORLD'S HIGHEST PREVALENCE
The world's highest
prevalence of Parkinson's Disease by far has been found among the Amish
community, where Parkinson's Disease is two to three times more prevalent than
anywhere else in the world. The Amish are a devoutly
religious
community,
primarily in the North East of the U.S.A.,
who believe in the
literal interpretation of the Bible.
The prevalence of Parkinson's Disease amongst the Amish community is 970
per 100,000, which is enormously high. They are afflicted by genetic disorders.
So it was thought that the cause might be genetic. However, the more closely
related they were, the less they were affected. They are primarily involved in
agriculture, and most of them use pesticides, but the effect of pesticides was
not assessed by the researchers.
The
world's next highest prevalence of Parkinson's Disease is in the vicinities of
ferromanganese plants near Brescia in Italy, with 407 people per
100,000 population. Manganese concentrations in settled dust were found to
be significantly higher in the surroundings and downwind from the
ferromanganese plants. In high concentrations, manganese is a known cause
of Parkinson's Disease.
The world's highest
prevalence of Parkinson's Disease of any region is in Nebraska, U.S.A. with 329.3 people
per 100,000 population. It is possible that there is a very high
prevalence of Parkinson's Disease in
Nebraska due to the heavy use of insecticides in what is largely a
farming area.
The U.S.A. is the country as a whole with the world's highest prevalence
of Parkinson's Disease. The U.S.A. has a high life expectancy that would
enable a larger number of people with Parkinson's Disease, but it is also
easier to be diagnosed with a medical disorder in the U.S.A..
The Parsi community of
Mumbai, India have a prevalence of Parkinson's
Disease of 328.3 per 100,000 population, which is almost in excess of that
found in Nebraska. This is despite
India as a whole having a low
prevalence. The Parsi practice Zoroastrianism, a
religion based on the teachings of Zoroaster. As part of their religion,
the Parsis burn Aspand seeds to rid their children
of the Evil Eye,
which is the name for
a sickness transmitted by someone who is
envious, jealous, or covetous.
The fumes are often inhaled. Aspand seed is the richest natural source of
two alkaloids, harmine and harmaline. They are a type of
drug known as MAO Inhibitors, which are also used in Parkinson's Disease.
Long term use of MAO inhibitors, eventually has the
opposite effect, and so may cause the high
prevalence of Parkinson's Disease amongst the Parsi.
WORLD'S LOWEST PREVALENCE
Ethiopia has the world's lowest
recorded prevalence of Parkinson's Disease. At a rate of only 7 per
100,000 it is far below the world's highest prevalence rate of 329
per 100,000 in Nebraska, U.S.A.. As Parkinson's Disease tends to be more
common in older people, the very low prevalence in Ethiopia may result
from the very low life expectancy in Ethiopia. Few prevalence studies have
been carried out in African countries. For most African countries the
figures are not known. If they were, other countries in the same region as
Ethiopia, or even in other parts of Africa may produce even lower
prevalence figures than those of Ethiopia.
PREVALENCE BY COUNTRY
The prevalence for each country per 100,000 of population, in those
countries in which it is known, from highest to lowest is :
U.S.A. 329-107,
Japan 193 - 76, San Marino 185, Faeroe Islands 206-183, Germany 183,
Spain 170-122,
Italy 168-104,
Finland
166-120,
Bulgaria 164-137, Estonia 152, Australia
146-104, Wales 142, England 139-121,
Portugal 135, Cuba 135,
Canada 125, China 119-57, Scotland
129, Norway
102, Japan 192 - 76, Sweden 76, New Zealand 76, Nigeria 67, Poland 66,
Jordan 59, Bolivia 50,
Libya 31, Colombia 31, Tanzania 20, Korea 19, Ethiopia 7. The prevalence differs from
country to country and can even differ within countries. The prevalence
amongst Bulgarian Gypsies is only one tenth of that found amongst other
Bulgarians.
The prevalence in the U.S.A. tends
to differ according to race, with Hispanics, then Whites, then Asians, then
Blacks being more prone.
However, other studies have given different results.
INCIDENCE RATES
The rate at which people with
Parkinson's Disease are newly diagnosed differs greatly according to the
country.
The incidence for each country, in which it is known, per 100,000 of population per year
from highest to lowest is :
Sweden 22.5-7.9,
Faeroe
Islands 21.1, U.S.A. 20.5-13.0, Japan 16.9 - 10.2, Estonia 16.8, Finland
16.6-14.9, Norway 12.6, England 12, Bulgaria 11.6, Netherlands 11.5, Italy
10.1, Russia 9.0,
Libya 4.5.
AGE DISTRIBUTION
In 1875, Henri Huchard (1844-1911) detailed the first case of
Juvenile Parkinson's Disease. He described a 3 year old child who had
all the clinical features of Parkinson's Disease. The youngest reported
case of Parkinson's Disease
since then is that of a 10 year old girl
from Okalahoma, who showed her first symptoms of Parkinson's Disease at
only
2 years old.
However, it is very uncommon for people under the age of 30 to develop
Parkinson's Disease.
Parkinson's Disease usually occurs when people are significantly older
than that and becomes increasingly more common with age.
The average age at which symptoms usually begin
differs from county to country, with the oldest average onset being in
Sweden 65.6, and Estonia 66.9.
The likelihood of Parkinson's Disease increases
sharply at the age of 60, and peaks in those aged 85 to 89 years old. The
likelihood of developing Parkinson's Disease starts to decline at 90 years
of age, and reduces even further after that. Parkinson's Disease is rare
amongst the very old - those people over 100, and even in those people who
are 110 to 119 years old.
GENDER DIFFERENCES
There
are more men than women with Parkinson's Disease. However, the ratio of
males to females differs a lot
according to the country. There is a stark contrast between a clear male
dominance in
Nigeria, and Japan, where far
more
Japanese women than men have Parkinson's Disease.
The ratio of males to females, in those countries in
which it is known, from highest to lowest is : Nigeria 3.3, Tanzania 2.72, Spain 2.55-2.06,
Taiwan 2.4, U.S.A. 1.91-1.0,
Finland 1.7, Norway 1.58-1.35, Netherlands 1.54, France 1.4, Canada
1.21-1.16,
Portugal 1.08,
San Marino 1.02, Sweden > 1.0, Argentina > 1.0,
Estonia < 1.0, Finland < 1.0, Italy
0.98, Netherlands 1.00-0.92, Russia 0.87, Japan 0.71 - 0.67.
RACIAL DIFFERENCES
Racial differences are best assessed in the same
country in order to nullify other factors. In the U.S.A., the proneness to
Parkinson's Disease was highest amongst whites, with an incidence of 45
per 100,000. Latinos were the next most prone with an incidence of 40 per
100,000. Least prone of all were African-Americans with an incidence
of
only 23 per 100,000. This gave African-Americans only a 43% chance of
being diagnosed in comparison to whites. Even after adjusting for all
possible factors, American-Americans still had less than half the
likelihood of developing Parkinson's Disease. The reason for this racial
difference in Parkinson's Disease is unknown. Observed racial differences
in the incidence of Parkinson's Disease are not explained at all by
differences in age, sex, income, insurance or healthcare utilization. In
another study the prevalence in the U.S.A., proneness to Parkinson's
Disease was also found to differ according to race, but with Hispanics,
then Whites, then Asians, then Blacks being more prone. Other studies have
given different results.
HAIR COLOUR
The risk of Parkinson's Disease increases according to
hair colour. People with black hair were found to be least prone to
Parkinson's Disease. People with brown hair were 40% more likely to
develop Parkinson's Disease. People
with
blonde hair were found to be around 60% more likely to develop Parkinson's
Disease. Worst at risk were people with red hair, for whom the risk of
Parkinson's Disease is nearly doubled. At first this association seems
odd, but hair colour and Parkinson's Disease share a common biochemistry.
The dopamine needed to relieve Parkinson's Disease is initially made from
L-tyrosine turning in to L-dopa. Coincidentally, Melanin, the pigment that
colours hair is also initially made by turning L-tyrosine in to L-dopa.
OCCUPATIONAL DIFFERENCES
Parkinson's Disease was found to be far more common
amongst welders.
Prevalence was also significantly higher amongst physicians, dentists,
teachers, lawyers, scientists, and religion-related jobs. Computer
programmers had a
younger age at PD diagnosis, and risk of diagnosis. Clerical occupations
were also positively associated with
Parkinson's Disease. Those people involved in manufacturing and
transportation were less likely to get Parkinson's
Disease.
Agricultural workers were more prone to Parkinson's Disease as were those
involved in hunting and forestry.
Parkinson's Disease is more common in
rural areas, but it differs according to the country.
The ratio of rural to urban cases, in those countries in which it is known,
from highest to lowest is : Italy 2.03-1.14, Estonia 1.14, Sweden 1.3.
However, another study found that the risk of Parkinson's Disease was not
significantly affected by farming work, by metal work, or by exposure to
pesticides, metals, or solvents.
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