L2.1: APPLICATION OF BIOSTATISTICS IN COMMUNITY AND PUBLIC HEALTH

Biostatistics

The language of public health

Incidence

measures the number of new cases of a disease over time. It reflects the risk of getting the disease.

Prevalence

measures the number of existing cases at a specific point in time. It reflects how widespread the disease is.

Burden

reflects how a disease persists, how many people are affected, and how interventions influence the number of cases.

Burden

If prevalence is prolonged, it is referred to as __

Prevalence

is usually measured over a year or a decade, and it accounts for the total number of people who have the disease. It is not easily reduced because there is no follow up. We do not know who recovered or not.

Incidence

With __, constant screening is done because new cases appear and the healthy population is monitored, which allows us to differentiate who has the disease and who does not.

• Quantify health problems (burden, prevalence, incidence)

• Detect outbreaks (epidemic thresholds, clustering)

• Evaluate programs (nutrition, HIV, TB, immunization)

• Generate evidence for policy decisions (PPAN, NTP, Dengue Prevention)

• Monitor community health status (FHSIS, eKonsulta, LGU scorecards)

Biostatistics enables public health practitioners to (5)

Outbreak

An increase in cases alone does not automatically mean an __.

Outbreak

In detecting __, we have to consider epidemic thresholds

Outbreak

No matter how many cases there are, an __ occurs only when the number exceeds what is normally expected.

Baseline data

Serve as our point of reference. For instance, last year’s flu cases or last year’s dengue cases help us determine what is normal for a given period.

+2

If the current number of cases exceeds the baseline by (1)__ standard deviations, this indicates an (2) . If it exceeds by only (3) __ standard deviation, it is just an (4)_ , meaning we should stay vigilant in case an outbreak develops later.

WHAT IS (1)?

Outbreak

If the current number of cases exceeds the baseline by (1)__ standard deviations, this indicates an (2)_ . If it exceeds by only (3) __ standard deviation, it is just an (4)_ , meaning we should stay vigilant in case an outbreak develops later.

WHAT IS (2)?

+1

If the current number of cases exceeds the baseline by (1)__ standard deviations, this indicates an (2)_ . If it exceeds by only (3) __ standard deviation, it is just an (4)_ , meaning we should stay vigilant in case an outbreak develops later.

WHAT IS (3)?

Alert

If the current number of cases exceeds the baseline by (1)__ standard deviations, this indicates an (2)_ . If it exceeds by only (3) __ standard deviation, it is just an (4)_ , meaning we should stay vigilant in case an outbreak develops later.

WHAT IS (4)?

+2

The true indication of an outbreak is __ standard deviations above the baseline.

Outbreak

exceeds the seemingly normal number of cases of the same period (there is a time component).

U=U

 is a DOH health promotion program that focuses on HIV transmission. It states that if a PLHIV (person living with HIV) is regularly tested and undergoing treatment to control the viral load, an undetectable viral load means the virus is untransmittable.

Undetectable equals Untransmissible

U=U stands for __

Zero

According to a DOH health promotion program, if a PLHIV has a viral load near __,  the person can no longer transmit the virus.

Person living with HIV

PLHIV stands for__

National TB Program (NTP)

For TB: We have the (1)__, which includes vaccination for TB prevention. The (2)__ vaccine is given to neonates within the first three months of life.

WHAT IS (1)?

BGC

For TB: We have the (1)__, which includes vaccination for TB prevention. The (2)__ vaccine is given to neonates within the first three months of life.

WHAT IS (2)?

Biostatistics

(1)__ provides the evidence needed to decide whether to institutionalize programs. (2)__ can support enacting programs into law or issuing operational guidelines for implementation.

WHAT IS (1)?

Evidence

(1)__ provides the evidence needed to decide whether to institutionalize programs. (2)__ can support enacting programs into law or issuing operational guidelines for implementation.

WHAT IS (2)?

Holistic

Our public health approach must be __. We should design solutions at the population level while also promoting health in general at the individual level.

Field Health Services Information System

FHSIS stands for __

FHSIS

Routine surveillance and field monitoring of health indicators.

eKonsulta

 A telemedicine platform used to extend clinical consultation, reporting, and case management remotely

LGU scorecards

Local government unit performance reports that include morbidity and mortality rates and other key indicators.

Determinants of health

These provide your overall health status. Your health can be affected by these determinants.

Determinants of health

This is where the idea of “you are a healthy person but you have these sets of characteristics” comes in.

• Socio-economic status

• Demographic factors

• Environmental factors

• Behavioral risk factors

Characteristics that make up your determinants of health (4)

Health status

Individually, your __ can be viewed in terms of mortality rates, morbidity/disability, and well-being

Mortality rates

are important when evaluating services

Morbidity

Refers to how many people get sick

Disability

Refers to how many people who get sick lose the capacity to partake in daily or societal functions

Well-being

concerns how you view your health or life, and it also affects your health status

Health system

The determinants of health provide information to the (1)__, which is very comprehensive. In terms of policy, financing, and human resources, these determinants guide how we should offer services. The services we offer then influence (2)__. These health system components help either improve well-being or reduce morbidity and mortality.

WHAT IS (1)?

Health utilization and coverage

The determinants of health provide information to the (1)__, which is very comprehensive. In terms of policy, financing, and human resources, these determinants guide how we should offer services. The services we offer then influence (2)__. These health system components help either improve well-being or reduce morbidity and mortality.

WHAT IS (2)?

Primary data

Collected by the researcher firsthand to suit his/her objectives

Secondary data

Derived from another source that may have other objectives for collecting the data

Query

Primary Data:

• __(1)

  • __(1.1)

  • __(1.2)

  • __(1.3)

• __(2)

  • __(2.1)

  • __(2.2)

WHAT IS (1)?

Observation

Primary Data:

• __(1)

  • __(1.1)

  • __(1.2)

  • __(1.3)

• __(2)

  • __(2.1)

  • __(2.2)

WHAT IS (2)?

• Interviews

• Questionnaires

• Focus group discussion

Primary Data:

• __(1)

  • __(1.1)

  • __(1.2)

  • __(1.3)

• __(2)

  • __(2.1)

  • __(2.2)

WHAT IS (1.1), (1.2), and (1.3)?

• Direct observation

• With measuring tools

Primary Data:

• __(1)

  • __(1.1)

  • __(1.2)

  • __(1.3)

• __(2)

  • __(2.1)

  • __(2.2)

WHAT IS (2.1) and (2.2) ?

Interview

For __ in public health, this is not simply a basic survey. Our lens in public health is to seek determinants of health. When you _ someone in the community, you ask questions related to these determinants.

Focus group discussion

In terms of children, how can you engage with them? You can conduct __ in the form of storytelling. From there, you can observe the child’s learning. This is a primary query type. Your act of asking questions is the query.

True

You can also incorporate observation into storytelling sessions

• review of records

• electronic databases

Two types of secondary data

Census

Type of review of records:

This can be used because it is a public document

Registries

Type of review of records:

These are also public documents, such as death, birth, and marriage registries.

False

Marriage is not included in registries because it helps us understand the reproductive capacity of a nation.

• Census

• Registries

• Hospital records

• Insurance records

• School records

Types of review of records (5)

Ethics clearance

For Hospital records, Insurance records, and School records — you need extensive review or (1)__ to access them. These are sensitive data sources. Individually, patients and students have personal information that must be protected. It is not outright prohibited to use these sources, but you must justify how, when, and where the data will be used. This is where the concept of (2)__ becomes essential, as we are dealing with (3)__.

WHAT IS (1)?

Anonymity

For Hospital records, Insurance records, and School records — you need extensive review or (1)__ to access them. These are sensitive data sources. Individually, patients and students have personal information that must be protected. It is not outright prohibited to use these sources, but you must justify how, when, and where the data will be used. This is where the concept of (2)__ becomes essential, as we are dealing with (3)__.

WHAT IS (2)?

Data Privacy

For Hospital records, Insurance records, and School records — you need extensive review or (1)__ to access them. These are sensitive data sources. Individually, patients and students have personal information that must be protected. It is not outright prohibited to use these sources, but you must justify how, when, and where the data will be used. This is where the concept of (2)__ becomes essential, as we are dealing with (3)__.

WHAT IS (3)?

Electronic databases

A type of secondary data that are usually open-source—open to the public, open access, and free to use. However, there must still be fair use. Even if access is free, the data should be used for academic, research, or public health purposes.

False

Even if access to electronic databases is free, the data should never be used for academic, research, or public health purposes.

• Descriptive study

• Cross-sectional study

• Case-control study

• Cohort study

• Experimental study

Examples of primary data based on the method of collection (5)

Cross-sectional study

Which type of primary data based on the method of collection:

In terms of time, you collect data only once. In a specific period of time, dito ka lang nag-collect. (If longitudinal, there would be a time range.)

Case-control study

Which type of primary data based on the method of collection:

we compare those with the condition to those without.

Cohort study

Which type of primary data based on the method of collection:

 we group participants into cohorts.

Experimental study

Which type of primary data based on the method of collection:

We can test treatments or interventions. Examples include testing the effectiveness of tawa-tawa against dengue, or the effectiveness of papaya against dengue or dengue hemorrhagic fever.

Observational research

Which descriptive research methods:

record behavior as it occurs without manipulating the variables

Survey research

Which descriptive research methods:

send surveys to selected groups and use the data to inform business decisions

Case study

Which descriptive research methods:

study multiple parties and compile findings into one case study on a subject

Interviews

Which descriptive research methods:

interview one party to gather data on a specific individual’s experience

Census

Which type of secondary data based on the method of collection:

• Population-based

  • __ - it involves a large amount of data (four years’ worth) that needs to be synthesized for population planning. In a _, the total population is accounted for, meaning everyone is included.

Civil registry

Which type of secondary data based on the method of collection:

• Population-based

  • __ - This includes birth certificates, reports of birth, marriage certificates, and death certificates.

Population survey

Which type of secondary data based on the method of collection:

• Population-based

  • __ - These can be conducted, but a specific number of households must be calculated to participate. Even in population surveys, sampling is usually applied; the survey may only cover a portion of the population.

census and civil registration

Classification based on the group of individuals from whom data were obtained:

Total Population

sample survey or population survey

Classification based on the group of individuals from whom data were obtained:

Representative subpopulation

civil registration

Classification based on frequencey by ehich data are generated:

Continuous

census and sample survey

Classification based on frequencey by ehich data are generated:

Periodic

Individual-level (patient charts, outpatient registers)

Which type of secondary data based on the method of collection:

• Institutional-based

  • __ - In community and public health, these sources are useful for examining biomarkers, monitoring how many patients undergo check-ups, and assessing individual health data within an institution.

Service-level (EPI reports, TB program data)

Which type of secondary data based on the method of collection:

• Institutional-based

  • __ - These sources show the coverage of programs. For example, how many TB patients are enrolled in DOTS (Directly Observed Treatment, Short-course), where medication intake is closely monitored. This level evaluates service delivery and program effectiveness.

Resource-level (HR inventory, facility readiness)

Which type of secondary data based on the method of collection:

• Institutional-based

  • __ - These sources assess your institution’s capacity to support public health programs.

Primary data

Which type of data is this:

Strengths

• High control over measurements

• Flexible and specific to research objectives

• Better ability to stratify by sex, age, barangay, socioeconomic group

Secondary data

Which type of data is this:

Strengths

• Timely (updated regularly, unlike primary data which is usually periodic), cheap, readily accessible

• Useful for trend analysis (10-20 years) (registries are secondary data and allow trend analysis)

• Enables large-scale population inferences

Primary data

Which type of data is this:

Limitations

• Expensive (especially if you are collecting the data yourself) and time-consuming (without careful planning, data collection can be difficult)

• Potential recall bias (interviews) (it can be challenging to follow up for clarifications; missing responses may need to be omitted)

• Small sample sizes in barangay studies

Secondary data

Which type of data is this:

Limitations

• Data may not align with research objectives (some variables may be unnecessary)

• Incomplete fields (e.g., missing cause of death; the immediate cause in hospital records may not be that accurate)

• Harder to stratify (barangay-level data often unavailable; data may be generalized)

Data requirement

Consideration in Selecting the Type of Source of Data

What indicators do you need? Anong mga determinants of health yan?

Sensitivity issues

Consideration in Selecting the Type of Source of Data

STI data, adolescent health, household income

Logistics

Consideration in Selecting the Type of Source of Data

manpower, training, cost

Data quality & utility

Consideration in Selecting the Type of Source of Data

completeness, consistency, validity

True

When it comes to presenting data that is less than 10, it has to be textual.

Textual

Type of Data Presentation in Community and Public Health:

A total of 2,303 individuals participated in the national health literacy survey, of which 2,146 respondents were able to complete the questions on functional health literacy. Cases with missing data for at least one variable were excluded from the analysis for this study. The final set of data used in the analysis included 1,997 participants (86.7%). Those categorized as having adequate FHL were 62.7%. The results for objective no.1 is presented in Table 1 (baseline assessment of the FHL level by characteristics of study participants).

Reference: Tejero, L. M. S., Siongco, K. L. L., Pinlac, P. A. V., Co, K. C. D., & Tolabing, M. C. C. (2022). Associations of functional health literacy with socioeconomic and demographic status among Filipinos. BMC Public Health, 22(1), 2198.

Frequency tables

Type of Data Presentation in Community and Public Health:

Categorical summary tables

Type of Data Presentation in Community and Public Health:

2×2 tables

Type of Data Presentation in Community and Public Health:

Risk Ratio

• used for cohort

• Aka relative risk, incidence rate, or attack rate

• Compares the risk (probability) of developing an outcome among exposed individuals to the risk among unexposed individuals over a defined period of time.

number of new cases ÷ total population at the start of study

Formula for incidence

Incidence in exposed ÷ Incidence in unexposed

Formula for risk ratio (cohort)

Odds ratio

• used for case control and cohort

• Compares the odds of exposure (or outcome) between two groups

odds of exposure among cases/odds of exposure among controls

Formula for odds ratio (case control)

odds of disease among exposed ÷ odds of disease among unexposed

Formula for odds ratio (cohort)

Odds ratio

Only measure of association that can be used by case control studies

Exposed cases ÷ Unexposed cases

Formula for Exposure odds among cases