Takano and colleagues’ paper [1] on the association between proximity
to ‘walkable green spaces’ and longevity in senior citizens in Tokyo will
be of interest to those involved in promoting health in its broadest
sense. However, this study has a number of methodological limitations,
the authors draw conclusions that are not supported by their results and
the study does not merit the largely uncritical r...
Takano and colleagues’ paper [1] on the association between proximity
to ‘walkable green spaces’ and longevity in senior citizens in Tokyo will
be of interest to those involved in promoting health in its broadest
sense. However, this study has a number of methodological limitations,
the authors draw conclusions that are not supported by their results and
the study does not merit the largely uncritical responses published
elsewhere in the Journal.[2-5]
Only 3144 individuals of 7362 contacted (42.7%) agreed to take part
in the survey. This response rate leads to the potential for substantial
selection bias which is not discussed by the authors.
The questions used to determine proximity of participants to
“walkable green spaces” are not explicitly described and their
appropriateness can not be determined. Asking if participants lived
“near” to a place for taking a stroll will lead to highly subjective
answers. In particular, those who do take strolls may be more likely to
report proximity to such places merely because they are more aware of
them. An objective measure of proximity to green spaces and a clear
definition of what constitutes ‘green’ would have significantly
strengthened the study.
Takano et al. claim that they make adequate control for socio-economic
factors by including a measure of “monthly living expenses”. However, it
is not clear how this is calculated and whether it is an appropriate and
recognised measure of socio-economic status in Japan.
The measure of functional status used – whether participants required
help to get out of bed – is simplistic. Considering the number of
validated measures of functional status available, the use of this measure
requires further justification.
In view of these limitations, it is clear that a number of the
conclusions drawn in the paper are unfounded. The authors find an
association between their measures of proximity to green spaces and
longevity in this cohort. This is not evidence of causation and certainly
not evidence that “walkable green…spaces near the residence significantly
and positively influenced five year survival”.
As discussed above, socio-economic factors may not have been
adequately controlled for. The association reported may not remain “even
after excluding the influence of socioeconomic conditions”. In
particular, it is possible that more affluent individuals, who generally
live longer,[6] are also likely to live in ‘greener’ neighbourhoods.
Finally, the authors suggest throughout this paper that proximity to
green spaces has a positive influence on longevity via an effect on
physical activity. However, no data is supplied on the physical activity
of participants. Such data would have added substantially to the authors
ability to conclude that such a causal chain exists.
Whilst this paper is certainly novel, the authors’ conclusions should
not be accepted uncritically. Readers and commentators should not allow
their personal convictions that green spaces must be a public good to
overshadow their critical appraisal skills. Evidence based policy making
is at least as important as evidence based medicine.[7]
References
(1) Takano T, Nakamura K, Watanabe M. Urban residential environments
and senior citizens' longevity in megacity areas: the importance of
walkable green spaces. Journal of Epidemiology & Community Health
2002;56:913-918.
(2) Baum F. Health and greening the city. Journal of Epidemiology &
Community Health 2002;56:897-898.
(3) Ashton J. Health and greening the city. Journal of Epidemiology &
Community Health 2002;56(896).
(4) McKenna J. Health and greening the city. Journal of Epidemiology &
Community Health 2002;56:896.
(5) Duhl L. Health and greening the city. Journal of Epidemiology &
Community Health 2002;56:897.
(6) Acheson D. Report of the independent enquiry into inequalities in
health . London: Stationary Office, 1998.
(7) Cummins S, Macintyre S. "Food deserts" - evidence and assumption in
health policy making. British Medical Journal 2002;325:436-438.
A recent article in Nature magazine Polls take heavy toll -- Suicide rises under
conservative rule, 20 September 2002 discusses the correlation of conservative governmental
rule, and suicide, in England and Australia, over the
last hundred years, and cites the article by Page A et al. as one of...
A recent article in Nature magazine Polls take heavy toll -- Suicide rises under
conservative rule, 20 September 2002 discusses the correlation of conservative governmental
rule, and suicide, in England and Australia, over the
last hundred years, and cites the article by Page A et al. as one of
two, in footnotes, in confirmation/support of this
finding.
Such a finding has immediately made its way into the
political pages here in the States, trumpted by the
Liberals as proof of the failings of conservative
rule. (The labels are different here in the US).
I differ with your conclusions, and support this
differing by referring you, on an inquiry basis,
between professionals, to: http://www.vakkur.com/psy/sui_medscape_excerpts.htm
This discusses suicide trends in many countries, and
shows that peaks occurred in the 1980s worldwide, at
least data-wide, more widespread than conservative
rule in UK/ Australia. Perhaps the studies findings
should be qualified accordingly.
Table 2 International General Population Suicide
Rates (fatalities per 100,000/year): 1970-1998
Country
1970
1975
1980
1985
1988
1994-98
Hungary
34.8
38.4
44.9
44.4
41.3
32.9
Finland
21.3
25.0
25.7
24.6
28.4
24.7
Belgium
16.5
16.2
21.7
23.1
22.7
21.3
Switzerland
18.6
22.5
25.7
25.0
22.4
20.6
Austria
24.2
24.1
25.7
27.7
24.4
19.6
France
15.4
15.8
19.4
22.6
20.7
19.3
Denmark
21.5
24.1
31.6
27.7
26.0
17.1
Czechoslovakia
25.2
21.9
20.0
18.9
17.7
15.9
Germany
21.3
20.9
20.9
20.7
17.6
14.4
Poland
11.2
11.3
10.7
13.3
12.2
14.4
Sweden
22.3
19.4
19.4
18.2
18.9
14.3
Norway
8.4
9.9
12.4
14.0
16.8
12.7
Ireland
1.8
4.7
6.3
7.8
7.5
11.4
United States
11.2
12.2
12.1
12.0
11.2
11.3
Iceland
13.2
10.1
10.5
13.2
14.0
10.1
Netherlands
8.1
8.9
10.1
11.3
10.3
10.1
Spain
4.2
3.9
4.4
6.5
7.2
8.6
Italy
5.8
5.6
7.3
8.3
7.7
8.3
United Kingdom
7.9
7.5
8.8
9.0
8.7
7.1
Portugal
7.5
8.5
7.4
9.7
8.0
5.7
Greece
3.2
2.8
3.3
4.1
4.1
3.6
Overall
14.5
14.9
16.6
17.2
16.6
14.3
Data are adapted from Mdkinen and Wasserman D, 1997
[71]; American
Association of Suicidology, Data for 1998[67]; and
WHO, 2001.[70]
Rates are ranked in descending order for the most
recent year.
MH- England (UK) is third from the bottom, the least
suicidal
societies are at the bottom, and Hungary Finland
Belgium and
Switzerland are at the top. I find it difficult to
classify these
four countries as MORE consevative, and England,
Portugal and Greece
as less conservative.
MH - Over time, starting with England, we see a peak
at the 1985
point, 9.0. Portugal and Greece also have this peak,
as does the
overall; Also peaking are, from the top, Belgium,
Swtzerland
(slightly more 1980), Austria, France, (Denmark in
1980), Czeckos
(1980), Germany, Poland, Sweden (1980), Norway,
Ireland, US, Iceland,
Netherlands, -- SPAIN is on a climb Italy is
plateauing, UK has
the spike these authors attributed to their own
policies, and at the
low end, the suicide immune societies, the 1985 data
also show
increases in this mid 1980s time period.
MH - Whatever was happening, it wasn't the Tories.
Britannia does not
still rule the waves.
MH- Further, in this article, regional differences are
noted within
countries, and the China Japan differences are noted.
Chine is pretty
high. Buncha Tories in rice paddies, eh, To Be Rich Is
Glorious.
"National and regional suicide rates vary widely. They
recently
averaged 14.5/100,000 per year internationally,
varying at least 10-
fold between countries. Rates per 100,000 population
ranged from 3.6
in Greece to 33 in Hungary, with intermediate rates of
10-20 in
central and northern Europe and the United States
(Table 2).
[67,70,71] In the United States, the annual rate per
100,000 has held
steady at about 11 in recent decades, but with wide
state and
regional differences, ranging from 22.7 in Nevada to
7.2 in New
Jersey and from 17.2 in the Mountain region to 11.3 in
the Pacific
region.[67]
Annual suicide rates in Asian countries include
300,000 reported
suicides in China (32.3/100,000), the only country
with a greater
risk among women than men.[72] In Japan, there are
about 20,000
suicides/year (17/100,000).[73]
[Editorial note: China's suicide rate (32.3) is
greater than Japan's
(17/100k) despite publicity of Japan's suicide rate;
both are higher
than the US rate (11/100k).]"
Thus the matter is not as simple as polls and pols.
Peruvians and Nepali people have something to share -
endless social violence. Nepal does not have a colonial ruler and so often does not have access to the modern world.
Our community has undergone very tramatic experiences of soldiers dying and rebels on the screen every day. This may account for the recent sharp rise in mental disorders.
Peruvians and Nepali people have something to share -
endless social violence. Nepal does not have a colonial ruler and so often does not have access to the modern world.
Our community has undergone very tramatic experiences of soldiers dying and rebels on the screen every day. This may account for the recent sharp rise in mental disorders.
The method applied in the article by JJ Miranda and E Vílchez is very
impressive and informative. We and our friends in the Psychiatry Department, would like to keep in touch with the authors to know more about the outcome of the program.
The straw poll was an interesting idea and an excellent and precise
result.
Now, we expect that the Ministers of Health, who actually are
voting, consider the capacity and experience of Dr Mirta Roses as the
voters in your poll did. Besides, this is an excellent opportunity to have
a woman in this position at PAHO, for the first time.
The great majority of South America and the Caribbea...
The straw poll was an interesting idea and an excellent and precise
result.
Now, we expect that the Ministers of Health, who actually are
voting, consider the capacity and experience of Dr Mirta Roses as the
voters in your poll did. Besides, this is an excellent opportunity to have
a woman in this position at PAHO, for the first time.
The great majority of South America and the Caribbean are suporting
this. Isn't it amazing that the North American countries and European
countries (except UK) are going in a separate way, using a more
"political" criteria rather than a technical one, different from the
Latina American countries?
The forthcoming election at PAHO ia a very serious matter. The Latin
American countries have passed, or are passing, through very hard times:
Mexico (Tequilla crisis), Colombia (Drugs and civil war) Argentina
(Economic crisis) etc. and the near future will be the most difficult in
relation to the expected social demands. Public Health should be prepared
to face important challenges.
The forthcoming election at PAHO ia a very serious matter. The Latin
American countries have passed, or are passing, through very hard times:
Mexico (Tequilla crisis), Colombia (Drugs and civil war) Argentina
(Economic crisis) etc. and the near future will be the most difficult in
relation to the expected social demands. Public Health should be prepared
to face important challenges.
Therefore, it is not time for a innexperient young professional, like
Mr Sepulveda, to try out some "new ïdeas". By the way, when we read
his statements we only see old and traditional approachs! This is not what
we need.
And it is said that he will use the advisors of the "World Bank" and
"Harvard" friends to tell him what to do! We had enough of them already
with disastrous results.
On the other side, the Argentinian candidate has an real impressive
curriculum and "gras root experience": worked in our caribbean setting for
several years, at the Epidemiological Center in Trinidad and Tobago, in
Dominican Republic and also in Bolivia. In the last few years she has
coordinated the cooperation of PAHO with the countries and have done a
very good job under dificult circumstances and minimal resources. She is
honest, transparent and a real team builder!
We expect our Ministers of Health to do the right thing. Dr Roses is
the person for this job at this time.
I would like to ask: where are the new ideas for PAHO?
Certainly not in the writings prepared by Dr Sepulveda for his
campaign.
On the other side, he has no proven experience with any international
program so far, much less in conducting a serious Institution like PAHO.
Latin America and the Caribbean are not places for an ambitious,
inexperienced person to try out "new ideas".
The professionals working for Public Health in the region and those
working with PAHO, fully committed with their work, like Dr Mirta Roses,
are well prepared for the challenges facing our countries in the near
future.
Dr Llanos also worked with PAHO before...he should knows that!
I thank Dr Adamiak for her careful reading of the glossary.
I believe the confusion may be motivated by the fact that the sentence she
refers to is not as clearly stated as it could have been. By "in the case
of continuous dependent variables" I meant more precisely "when the
response variable is normally distributed and the link function is
identity (ie models usually referred to as linear models)". By "i...
I thank Dr Adamiak for her careful reading of the glossary.
I believe the confusion may be motivated by the fact that the sentence she
refers to is not as clearly stated as it could have been. By "in the case
of continuous dependent variables" I meant more precisely "when the
response variable is normally distributed and the link function is
identity (ie models usually referred to as linear models)". By "in the
case of non-normally distributed variables (for example, logistic models)"
I meant more precisely "in the case of other models such as logistic
models (where the response variable is the log odds of a binary outcome)".
Of course, as Dr Adamiak notes, linear regression could be performed
using dichotomous variables, and continuous variables can be dichotomized
and modelled using a logistic model. The essence of the statement however
is correct: In the linear model (as defined above), regression
coefficients derived from random effects and population-average models are
equivalent but in the logistic model they are not (see references 46 and
47 in the glossary for more details). I apologize for the confusion and
thank Dr Adamiak for the opportunity to clarify this.
It would be interesting to know the overall health condition of the
subjects. Were they average weight, average stressed occupations, diets.
What other environmental conditions could have contributed to their heart
problems, if any.
The Authors draw conclusion that the use of acute hospital beds does
not increase as the population ages, which is a result from a seven year
cohort study in Germany. The problem is however that there are supply
related factors, which can strongly affect the results. It is known that
there are substitutions between different forms of care.[1] The
days spent in hospitals and the mortality rates, in part...
The Authors draw conclusion that the use of acute hospital beds does
not increase as the population ages, which is a result from a seven year
cohort study in Germany. The problem is however that there are supply
related factors, which can strongly affect the results. It is known that
there are substitutions between different forms of care.[1] The
days spent in hospitals and the mortality rates, in particular among the
oldest populations, are affected by the access to elderly care, e.g.
providers of palliative care in the terminal stage of life.[2] In Sweden the reform of the care for the elderly meaning transfer
of responsibility for the care of the elderly to municipalities led to an
increase of death rates in some of the nursing homes providing long term
care and after care to the elderly people.[3,4] Also, the supply of beds at geriatric departments might be
associated with the number of inhospital deaths as opposed to deaths
occurring in other places.
The stable patterns in inhospital death rates among German inpatients
might be to a large degree explained by the growing supply of other forms
of care of the elderly, which authors do not appear to take into account
in their calculations and the following discussion. The impact of supply
of various kinds of inpatient beds is an important confounder in studies
that calculate inhospital mortality and beds use as proxies for morbidity
and related mortality (or health outcomes) without considering effects of
supply and proximity known by all health economists and epidemiologists.
Proxy measures or performance indicators such as use of hospital beds are
conceptually different from outcome indicators or measures of health care
needs.[5-8] Use or supply is often confounded with needs and a
serious methodological problem.[9,10]
The knowledge about the supply inducement is used as a rationale
behind many management decisions in health care, so called "chains of
care" and by HMO in USA. Patients treated for acute conditions are
transferred to other forms of after care when their condition stabilizes.
As Ashton et al.[11] point out physicians will discharge patients
prematurely if there is a safety net outside hospitals, which can provide
prompt aftercare. Some patients are requiring to be discharged and die at
home, which is a consequence of free choice, often used by terminally ill
cancer patients. Thus, the conclusion about health care needs of acute
care among the German as well other populations based on consumption of
hospital days as proxy for health care needs is strongly biased. It is
rather a matter of provision of inpatients beds and integration between
various providers.[4] Inpatient beds might in fact be
located outside hospitals or in patient homes, and those deaths are not
registered in hospital discharge data bases, which often serve as the
primary source of information in many studies. It must be more appropriate
to calculate total death rates to make inferences about changing health
care needs among populations. A health care system perspective[12] and account into total population instead solely into use of
acute care hospitals and inhospital deaths would be more fruitful in the
context of projections of health care needs.
Grazyna Adamiak
References
(1) Culyer AJ. The morality of efficiency in health care – some
uncomfortable implications. Economics of health care systems. Health
Economics 1992;1:7-18.
(2) Fisher J, Wennberg JE, Stukel TA, Sharp SM. Hospital readmission
rates for cohorts of medical beneficiaries in Boston and New Haven.
New England Journal of Medicine 1994;331:989-95.
(3) The Federation of County Councils. Place of death project (Plats för
död-projektet) http://www.lf.se
(4) Andersson G, Karlberg I. Integrated care for the elderly. The background
and effects of the reform of Swedish care of the elderly. International
Journal of Integrated Care (IJIC) 2000. http://www.ijic.org/
(5) Morrill RL, Earickson R. Hospital Variation and Patient Travel
Distances. Inquiry 1968;5:26-34.
(6) Wennberg JE, Barnes BA, Zubkoff M. Professional uncertainty and the
problem of supplier-induced demand. Social Science and Medicine
1982;16:811-834.
(7) Hornbrook MC. Practice Mode and Payment Method. Effects on Use,
Costs, Quality and Access. Medical Care 1985;23:484-511.
(8) Giuffrida A, Gravelle H, Roland M. General Practice. Measuring
quality of care with routine data: avoiding confusion between performance
indicators and health outcomes. British Medical Journal 1999;319:94-98.
(9) Carr-Hill RA, Jamison JQ, O'Reilly D, Stevenson MR, Reid J, Merriman
B. Risk adjustment for hospital use using social security data: cross
sectional small area analysis. British Medical Journal 2002;324:390.
(10) Gibson A, Asthana S, Brigham P, Moon G, Dicker J. Geographies of need
and the new NHS: methodological issues in the definition and measurement
of the health needs of local populations. Health and Place 2002;8:47-60.
(11) Ashton CM, Wray NP. A conceptual framework for the study of early
readmission as an indicator of quality of care. Social Science and
Medicine 1996;43(11):1533-1541.
(12) Nutting PA, Shorr GI, Burkhalter BR. Assessing the Performance of
Medical Care Systems: A Method and its Application. Medical Care
1981;19(3):281-296.
I have found that under the heading Population-average models (page
592), when comparing the multilevel models to population-average models,
the Author is stating that in the case of continuous dependent variables
the coefficients are mathematically equivalent in the marginal models. In
the next phrase the Author suggest "...but in the case of non-normally
distributed variables (for example, logistic...
I have found that under the heading Population-average models (page
592), when comparing the multilevel models to population-average models,
the Author is stating that in the case of continuous dependent variables
the coefficients are mathematically equivalent in the marginal models. In
the next phrase the Author suggest "...but in the case of non-normally
distributed variables (for example, logistic models) etc.".
Linear regression might be performed using dichotomous variables as
well as dependent variables. The issue of mathematical equivalence is some
what tricky, the value of dichotomous variables, if 1, might be also
regarded as continuous whether mathematically there is infinity and we can
continue to count 0.999999999 etc.
There is no contradiction between the first statement and the second,
after "but". Continuous variables might also be non-normally distributed,
which is quite common in the context of measurements in health care, for
example age distribution among inpatients is usually strongly skewed.
Logistic regression might be performed on normally distributed variables
as well.
The logistic regression is based on the assumption of binomial
distribution, which means that it does not matter if the variables are
normally distributed or not. Both in the multiple linear and the logistic
regressions there is an assumption about the variance of the outcome
variable. In the linear model there is an expectation that the variance of
the outcome variable is equal around the mean whether in the logistic
regression the variance depends only on the mean. The linear models model
the mean value of the outcome whether the logistic the logarithm of the
odds of the outcome (referred to as logit). The relationship of multiple
independent variables to outcome in the linear regression is such that the
mean value of outcome changes with linearly with multiple independent
variables. In the logistic model, the logit of outcome changes linearly
with multiple independent variables. Thus, both are based on the
assumption of linearity and averages appear to play a role in both.
Grazyna Adamiak
Reference
(1) Katz MH. Multivariable analysis. A practical guide for Clinicians. Cambridge:
Cambridge University Press.
Dear Editor
Takano and colleagues’ paper [1] on the association between proximity to ‘walkable green spaces’ and longevity in senior citizens in Tokyo will be of interest to those involved in promoting health in its broadest sense. However, this study has a number of methodological limitations, the authors draw conclusions that are not supported by their results and the study does not merit the largely uncritical r...
Dear Editor
A recent article in Nature magazine
Polls take heavy toll -- Suicide rises under conservative rule, 20 September 2002
discusses the correlation of conservative governmental rule, and suicide, in England and Australia, over the last hundred years, and cites the article by Page A et al. as one of...
Dear Editor
Peruvians and Nepali people have something to share - endless social violence. Nepal does not have a colonial ruler and so often does not have access to the modern world.
Our community has undergone very tramatic experiences of soldiers dying and rebels on the screen every day. This may account for the recent sharp rise in mental disorders.
The method applied in the article by JJ Mir...
Dear Editor
The straw poll was an interesting idea and an excellent and precise result.
Now, we expect that the Ministers of Health, who actually are voting, consider the capacity and experience of Dr Mirta Roses as the voters in your poll did. Besides, this is an excellent opportunity to have a woman in this position at PAHO, for the first time.
The great majority of South America and the Caribbea...
Dear Editor
The forthcoming election at PAHO ia a very serious matter. The Latin American countries have passed, or are passing, through very hard times: Mexico (Tequilla crisis), Colombia (Drugs and civil war) Argentina (Economic crisis) etc. and the near future will be the most difficult in relation to the expected social demands. Public Health should be prepared to face important challenges.
Therefore,...
Dear Editor
I would like to ask: where are the new ideas for PAHO?
Certainly not in the writings prepared by Dr Sepulveda for his campaign.
On the other side, he has no proven experience with any international program so far, much less in conducting a serious Institution like PAHO.
Latin America and the Caribbean are not places for an ambitious, inexperienced person to try out "new ideas"....
Dear Editor
I thank Dr Adamiak for her careful reading of the glossary. I believe the confusion may be motivated by the fact that the sentence she refers to is not as clearly stated as it could have been. By "in the case of continuous dependent variables" I meant more precisely "when the response variable is normally distributed and the link function is identity (ie models usually referred to as linear models)". By "i...
Dear Editor
It would be interesting to know the overall health condition of the subjects. Were they average weight, average stressed occupations, diets. What other environmental conditions could have contributed to their heart problems, if any.
Dear Editor
The Authors draw conclusion that the use of acute hospital beds does not increase as the population ages, which is a result from a seven year cohort study in Germany. The problem is however that there are supply related factors, which can strongly affect the results. It is known that there are substitutions between different forms of care.[1] The days spent in hospitals and the mortality rates, in part...
Dear Editor
I have found that under the heading Population-average models (page 592), when comparing the multilevel models to population-average models, the Author is stating that in the case of continuous dependent variables the coefficients are mathematically equivalent in the marginal models. In the next phrase the Author suggest "...but in the case of non-normally distributed variables (for example, logistic...
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