Disease Detectives B/C

[JoJoKeKe]

I had my regionals a few weeks ago, and we were asked to calculate the relative risk from mortality rates. Specifically the population in question was grouped based on elevation of residence, and the mortality rate of each group was given. I know that relative risk is basically the rate of a condition among the exposed divided by the rate among the unexposed, but how should we determine which groups are considered exposed and unexposed when we have several levels of exposure?

Lowest exposure level is set to one (index) when there is no unexposed group. If you have several different exposures, lowest risk group is used as index.

Could you give an example of a question where there are exposure "levels"? I've never seen anything like this on a test, but would like to add something like to my reference sheet. Thank you!

[yang573]

Lowest exposure level is set to one (index) when there is no unexposed group. If you have several different exposures, lowest risk group is used as index.

Could you give an example of a question where there are exposure "levels"? I've never seen anything like this on a test, but would like to add something like to my reference sheet. Thank you!

The first example that comes to mind is when you have people exposed to a particular exposure in different amounts, such as milligrams of lead. When that occurs, just create multiple 2x2 tables comparing each individual exposure level with the control/index level.

[Eggo]

I was at OC regionals this weekend, and my partner and I felt as if we were taking a green generation test. It asked us obscure facts about ecology, such as the various biomes of brazil, or how carbon emissions impacted the world. There was almost no link to epidemiology, except for the tiebreakers that asked about Hill's Criteria. I was thinking that maybe the Event Supervisor had interpreted population growth as ecology. Has anyone else seen a DD test with 90% Green Gen?

[Flavorflav]

I had my regionals a few weeks ago, and we were asked to calculate the relative risk from mortality rates. Specifically the population in question was grouped based on elevation of residence, and the mortality rate of each group was given. I know that relative risk is basically the rate of a condition among the exposed divided by the rate among the unexposed, but how should we determine which groups are considered exposed and unexposed when we have several levels of exposure?

Lowest exposure level is set to one (index) when there is no unexposed group. If you have several different exposures, lowest risk group is used as index.

Could you give an example of a question where there are exposure "levels"? I've never seen anything like this on a test, but would like to add something like to my reference sheet. Thank you!

Yang's answer is a good one - virtually everyone has some exposure to lead, radiation etc. and of course every one lives at some elevation, so there is no unexposed group, only a least exposed group.

[kanademi]

I was at OC regionals this weekend, and my partner and I felt as if we were taking a green generation test. It asked us obscure facts about ecology, such as the various biomes of brazil, or how carbon emissions impacted the world. There was almost no link to epidemiology, except for the tiebreakers that asked about Hill's Criteria. I was thinking that maybe the Event Supervisor had interpreted population growth as ecology. Has anyone else seen a DD test with 90% Green Gen?

ayyyy I was there at OC as well and I totally understand what you mean. I thought we were going to do alright on the event even though my partner got switched out, since I had studied the textbook pretty well and thought I had a pretty good grasp on epidemiology.

But then the first half of the test was all questions on climate change, and we got wrecked because we weren't prepared for those kinds of questions. I understand (somewhat) the reasoning behind them using climate change the way they did: the scenario talked about how climate change influenced migration. But then the questions didn't focus on the migration of people at all, only on the climate change. They even asked vocab specific to climate change.

Anyways, my question to you all is: how does one study for the population growth topics? Do you just have to read articles related to the topics and hope that you remember all the facts that they talk about? I thought the growth questions they asked would be mainly logical questions, not knowledge-based ones.

[yang573]

Does anyone know how to calculate OR and RR when one of the numbers in the 2x2 table is 0?

[LIPX3]

Does anyone know how to calculate OR and RR when one of the numbers in the 2x2 table is 0?

I think it is 0 or undefined, defending on what variable is 0.

[ampy1234567]

I saw on one of the nationals tests that you're supposed to add 0.5 to all the numbers on the table, but it's probably a better idea to just go with 0 or undefined anyways

[QuantumTech]

@people who have participated in state competition for Disease Detectives for multiple years: Have you seen questions or a table where they provide a disease name and ask what type of disease it is (bacterial, viral, fungal, etc.) and what vector causes it? I need to make space for stats tables (t-table, z-table etc.) so I need to free up some space. Right now my cheat sheet has background info on all the common diseases (where it is endemic, historical outbreaks, amount of people affected). Will that be useful on tests (I will memorize if I have too) or should I just delete it?

[maxxxxx]

@people who have participated in state competition for Disease Detectives for multiple years: Have you seen questions or a table where they provide a disease name and ask what type of disease it is (bacterial, viral, fungal, etc.) and what vector causes it? I need to make space for stats tables (t-table, z-table etc.) so I need to free up some space. Right now my cheat sheet has background info on all the common diseases (where it is endemic, historical outbreaks, amount of people affected). Will that be useful on tests (I will memorize if I have too) or should I just delete it?

I've only competed in Disease Detectives at states twice(and one of them was 4 years ago so I don't remember much) but they both had sections regarding an outbreak of a disease which asked questions about spread, treatment, and cause. Also my regionals test this year was 20% writing what kind of agent caused a disease. You should probably keep the specific disease info. I was also under the impression that if they expected you to look up z and t statistics they would provide the tables because that's a lot to ask the competitors of(the tables would take up a significant amount of a note sheet just to be readable, and it wouldn't comprise very much of the test).