Epidemiology of Substance Use Public Health

1
Adolescent Addiction Course February 2007
Epidemiology of Substance Use Public
Health
Martin Frisher Department of Medicines
Management Keele University http//www.keele.ac.u
k/schools/pharm/ drug-misuse/DrugMisuseDownloads.h
tm Harplands Hospital
2
Learning Objectives

• To consider
• Historical Development Of Public Health
• Types Of Public Health Analysis
• Surveillance And Prevention
• Ethical Issues
• Evidence Based Medicine
• Attributable Risk

3
Hippocrates
Hippocrates (430 - 370 B.C.)

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EPIDEMIOLOGY

• epi upon
• demos people
• logos study
• The scientific study of the distribution and
  determinants of health-related states or events
  in specified populations, and the application of
  resulting knowledge to the prevention and control
  of health problems

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Public Health in Greek Civilization

• Hippocrates - 460 BC
• Airs Waters and Places essays on the influence
  of climate water and situation on health
• Aristotle 384 BC
• Eudaimonia wellbeing of the whole person
• Minoan Civilisation 2,500 1,600 BC
• Environmental and social harmony in balance
  with Nature

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Victorian Visionaries

• Sir Edwin Chadwick
• 1800-1890
• Good economics to prevent the evils
• Chadwick contributed to a report of 1834 that
  led to legislation covering the national
  supervision of health, safety and social
  problems. He later brought through parliament the
  Public Health Act of 1848, which enshrined the
  principle that health care should be administered
  at a local level.

http//www.ukpha.org.uk/media/PowerPoint_Documents
/WanlessLeedsEvent.ppt.
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Victorian Visionaries

• Joseph Chamberlain
• 1836-1914
• Mayor of Birmingham
• High rates and a healthy city
• In the 1885 General Election Chamberlain was
  seen as the leader of the Radicals with his calls
  for land reform, housing reform and higher taxes
  on the rich.

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Victorian Values

• 1831 local business men forced doctors to
  retract diagnoses during Sunderland cholera
  outbreak
• Later a group of anti-quarantine businessmen on
  the Sunderland Health Board prevented the
  publication of new cases in an effort to stop
  quarantine being imposed
• London, 1848. MPs and vested interests managed
  to exclude London from the provisions of the
  Public Health Act.
• The Times 1854 The British Nation abhors
  absolute power. We prefer to take our chances
  with cholera and the rest than be bullied into
  good health

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Ten Great U.S. Public Health Achievements
1900-1999

• Vaccination
• Motor Vehicle Safety
• Safer Workplaces
• Control of Infectious Diseases
• Decline in deaths from coronary heart disease and
  stroke

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Ten Great Achievements (Continued)

• Safer and healthier foods
• Healthier mothers and babies
• Family Planning
• Fluoridation of Drinking Water
• Recognition of Tobacco Use as a Health Hazard
• CDCs Morbidity and Mortality Weekly Report
  (MMWR), April, 1999.

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Public Health in the 20th Century

• Plethora of allied medical professions (Nurses,
  Health Visitors, therapists etc)
• Growth of professions within local authorities
• Disengagement from the public
• Dominated by technological and curative fixes?
• www.countrysiderecreation.org.uk/pdf/Angela20Mawl
  e.pdf

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Population Survivorship Two Populations













th
17
century




2002

London, England
Age


United States

0

100






100


6

64


99


16

40


99


26

25


98


36

16


97


46
10


95


56

6


91


66

3


81


76





1






63


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John Snow (1813-1858)
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Spot Map of Fatal Cholera Cases in London, 1854
Source Ian R.H. Rockett. Population and Health
An Introduction to Epidemiology. Second edition.
Population Bulletin 54(4) 1999 6.
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Population Growth

Source Joseph A. McFalls, Jr. Population A
Lively Introduction. Third edition. Population
Bulletin 53(3) 1998 38.
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The Demographic Transition

• The demographic transition framework illustrates
  population growth in terms of discrepancies and
  changes in two crude vital rates mortality and
  fertility (ignores the third component of growth,
  migration)

21
Source Joseph A. McFalls, Jr. Population A
Lively Introduction. Third edition. Population
Bulletin 53(3) 1998 39.
22
Top 10 Causes of Death in the U.S. , 1900
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Top 10 Causes of Death in the U.S. , 2000
24
Source Ian R.H. Rockett. Population and Health
An Introduction to Epidemiology. Second edition.
Population Bulletin 54(4) 1999 9.
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Descriptive Epidemiology

• Magnitude of the Problem - how big?
• Person, Place, and Time
• - who, where, and when?

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Injury Deaths Worldwide by Leading Causes and
Intent, 1990
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PERSON

• Demographic characteristics e.g. age, sex, race,
  marital status, number of children
• Socioeconomic characteristics, e.g. social
  class, employment status, occupation
• Life style/behavior e.g. drinking
  alcohol/smoking marijuana and driving

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United States Suicide Rates by Age, Sex, and
Racial Group, 1999-2001
Data accessed through CDC Wonder
http//wonder.cdc.gov/mortICD10J.html
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PLACE

• Are the disease or injury cases
• geographically confined or pervasive?
• clustering around known potential pathogens,
  toxins, or other hazards?

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• Correlational (Ecological) Study uses data from
  entire populations to compare disease/injury
  frequencies in relation to putatively harmful
  (or beneficial) exposures during the same
  period of time or at different points in time
  (typically use secondary published data like
  vital statistics, censuses and national health
  surveys)

32
Source Len Evans. Traffic Crashes. American
Scientist 90 (3) 2002 246. http//www.dushkin.co
m/text-data/articles/34749/body.pdf
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Method of Difference (J.S.Mill)

• Examines differences among groups for clues as to
  why the groups disease rates or other health
  problems vary

34
Source Ian R.H. Rockett. Population and Health
An Introduction to Epidemiology. Second edition.
Population Bulletin 54(4) 1999 17.
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Method of Agreement

• Looks for commonality in groups that manifest the
  same health problem

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The Epidemiologic Triad
HOST
AGENT
ENVIRONMENT
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Levels of Prevention

• Primary
• Secondary
• Tertiary

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The Haddon Matrix
39
Source Ian R.H. Rockett. Injury and Violence A
Public Health Perspective. Population Bulletin
53(4) 1998 18. Adapted from G.S Smith and H.
Falk, Unintentional Injuries. American Journal of
Preventive Medicine 3(5) Supplement 1997143-163.

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Case Presentation

• Assume that you are the health director of a
  local health department.
• A community in your area is concerned with its
  high rate of childhood obesity and requests your
  help.
• How do you proceed?

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Develop an InitialStatement of the Issue

• The prevalence of obesity among the 327
  elementary school children in the community is
  35. With the support of parents, school staff,
  and community-based organizations, how can this
  obesity rate be reduced through lifestyle
  interventions?

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Quantify the Issue

• The prevalence of obesity was determined by a
  survey.
• The rate of obesity was found to increase by
  grade level.
• The rates were about equal in girls and boys.
• 100 minutes/wk provided at school for physical
  activity, but only 40 minutes is guided by a
  teacher.

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Search the Scientific Literature and Organize
Information

• Medline search
• Cochrane Collaboration
• Task Force on Community Preventive Services

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Task Force on Community Preventive Services

• Insufficient evidence to recommend
  classroom-based health education to provide
  information on managing health risks.
• Strongly recommended curricula and policies to
  increase the amount of moderate or vigorous
  activity, increase the amount of time in PE
  class, or the amount of time being active in PE.

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Develop an Action Plan

• Agreement is reached on a pilot project for the
  next school year involving reducing the lunch
  hour and increasing time in physical education
  with an emphasis on activities that get all
  children to be active.
• The program will be evaluated by all stakeholders
  (e.g., children will be surveyed)

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Definition of Evidence Based Medicine

• The integration of best research evidence with
  clinical expertise and patient values.

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Definition of Evidence Based Medicine

• The integration of best research evidence with
  clinical expertise and patient values.
• Sackett, D. L., Straus, S. E., Richardson, W. S.,
  Rosenberg, W., Haynes, R. B. (2000). Evidence
  based medicine How to practice and teach EBM
  (2nded.). London Churchill Livingstone.

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Factors Driving EBM

• Overwhelming size of the literature
• Inadequacy of textbooks
• Difficulty synthesizing evidence and translating
  into practice
• Increased number of RCTs
• Available computerized databases
• Reproducible evidence strategies

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Critique of EBM

• De-emphasizes patient values
• Doesnt account for individual variation
• Devalues clinical judgment
• Leads to therapeutic nihilism

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Parachute use to prevent death and major trauma
related to gravitational challenge systematic
review of randomised controlled trials. Smith
GC, Pell JP. BMJ 3271459-1461 2003.
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Improving the Qualityof the Science Base

• Moving beyond RCTs
• Transparent Reporting of Evaluations with
  Non-randomized Designs (TREND)
• Grading of Recommendations Assessment,
  Development and Evaluation (GRADE)

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Public Health Examples

• Bicycle helmet programs
• Community water fluoridation
• Family planning services
• Mosquito control programs
• Influenza vaccination

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Medical Care-Public Health Whats the Difference?

• Medical care is primarily curative
• Public Health is primarily preventive
• Public Health focuses on populations, while
  medical care focuses on individuals.

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Obesity and marketing

• Food advertising
• Food Standard Agency influences children
• Parents influences children (Chartered
  Institute of Marketing)
• Pre-school market 4.3billion per year
• 30 non-programme content during childrens
  viewing is for food
• UK kids
• 17 commercials per hour
• 10 food ads
• 95-99 will be processed and high in fat salt and
  sugar
• Total food advertising 600million per year
• Veggies/fruit 26 million per year

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CHOICE AND PUBLIC HEALTHNanny State or Public
Good?

• State influences health in
• Health safety issues
• Food, air water and soil quality
• Transport (including seat belts and helmets)
• Drinking and driving
• Legislation against dangerous and addictive drugs
• Need to distinguish between NHS service delivery
  and Public Health
• The public need the opportunity to choose health
  rather than what happens to them when they become
  ill (Kings Fund Discussion paper 2004)

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Drug use among adolescents How many cases could
be prevented by removing risk factors?

• Aims. Although a wide range of characteristics
  have been identified as risk factors for
  adolescent drug use, there is considerable
  uncertainty about how useful they are for drug
  prevention strategies.
• This study aims to identify significant risk
  factors and determine how their removal could
  alter the number of adolescent drug users.

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ATTRIBUTABLE RISK

• The attributable risk of disease given an
  exposure is simply the rate of disease
  (incidence) in the exposed people minus the rate
  in the unexposed people.
• So the attributable risk for lung cancer in
  smokers is, in essence, simply the rate of lung
  cancer amongst smokers minus the rate of lung
  cancer amongst non-smokers.
• The population attributable risk is an estimate
  of the proportion of disease or other outcomes in
  a community due to exposure to a specific factor.

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Drug use among Young Offenders

• Design. Cross-sectional interview study and
  teacher ratings of school performance.
• Setting. Wolverhampton, England.
• Participants. 180 young people referred to the
  Wolverhampton Youth Offending Team.
• Ninety-nine (55) had never used drugs, thirty
  (19) used occasionally and forty-six (26) used
  regularly (weekly).

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Prevalence of Risk Factors
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Risk Factors for Drug Use
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Risk factors (yes/no) and predicted probability
of drug use (regular/occasional/never).
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Attributable Risk

• There are 100 road traffic deaths among 2,000
  speeding drivers (risk 5) and 80 deaths among
  8,000 non-speeding drivers (risk 1). AR is
  calculated as the difference between the two risk
  estimates (i.e., 5 1 4). The percentage AR
  (AR) is the AR divided by the total risk among
  exposed cases (4 / 5 80).
• The PAR is calculated by expressing the
  percentage difference between the RTA rate among
  non-speeding drivers (80 / 8,000 1) and the
  Road Traffic Accident (RTA) rate among all
  drivers (180/10,000 1.8) as a proportion of
  the latter i.e., (1 1.8 / 1.8) 100.
• Thus 44 of fatalities among fast and slow
  drivers (i.e., the population of drivers) are
  attributable to speeding, assuming that speeding
  is causally related to RTAs.

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Population Attributable Risk (PAR)

• In the current study, factors such as familial
  drug use are powerful risk factors (adjusted OR
  22), but are relatively uncommon in the
  population (6).
• In contrast, current smoking is a relatively weak
  risk factor (adjusted OR 4), but occurs more
  frequently in the population (32).
• The adjusted population risk for familial drug
  use is 27, compared to 64 for smoking.
• This means that at a policy level, elimination of
  smoking could have a considerably greater effect
  on regular drug use than elimination of familial
  drug use if both were actually causal factors.

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The government is very keen on amassing
statistics. They collect them, add them, raise
them to the nth power, take the cube root and
prepare wonderful diagrams. But you must never
forget that every one of these figures comes in
the first instance from the village watchman, who
just puts down what he damn well pleases.

• Sir Josiah Stamp, British
• Economist (1880-1941)