Background Population Exposure Estimates Using E. coli O157 Case Interviews

Transcription

1 Background ulation Exposure Estimates Using E. coli O157 Case Interviews INTRODUCTION/INTENDED USE The following data comprise exposure frequencies for sporadic culture-confirmed Escherichia coli O157 cases that occurred in Minnesota from 2009 through Cases were interviewed with a detailed questionnaire about exposures that occurred in the 7 days prior to their illness onset ( Epidemiologists can use these frequencies to estimate the background exposure rate in the population for a particular food item or other exposure and then use this estimate in a binomial model comparison which is available in Epi Info 7 under StatCalc or as an excel spreadsheet at ( This can be useful to quickly evaluate potential hypotheses during the hypothesis generation phase of an investigation prior to conducting a more resourceintensive study method like a case-control study. Cases that were not interviewed, cases who reported international travel within the week prior to illness onset, and outbreak-associated cases, regardless of the transmission route, were not included in these data. Epidemiologists should carefully consider any potential biases arising from the use of E. coli O157 case exposure information to estimate background population exposure rates. Using E. coli O157 cases to estimate the background exposure rate in the population will likely introduce bias away from the null hypothesis when evaluating exposures that are risk factors for E. coli O157. For example, the percentage of sporadic E. coli O157 cases that were exposed to a known E. coli O157 risk factor such as ground beef is potentially higher than the true background rate of exposure to ground beef in the population. Epidemiologists should also consider if the food item under evaluation has seasonal consumption patterns, or if consumption of the food varies by gender or age. The questionnaire administered to E. coli O157:H7 cases was modified in Food exposure questions that were added to the interview questionnaire are indicated by an asterisk (*). Food exposures questions that were removed from the questionnaire in 2011 are indicated by a double asterisk (**). Another potential source for background exposure data is the FoodNet ulation Atlas of Exposures, ( For more specific exposure food frequencies to match the demographics of your current investigation, please contact Joshua.rounds@state.mn.us

2 DAIRY Overall Female Male Spring Summer Fall Winter Eggs Shredded cheese N/A N/A Processed cheese slices Block cheese String cheese Cheese curds N/A N/A Queso fresco or other Mexican style cheese Gourmet cheese (gouda, blue, other cow, goat or sheep cheeses)* N/A N/A Ice cream Frozen dessert N/A NA treats Yogurt Milk Unpasteurized milk Milk alternatives (soy, almond, rice milk)* N/A N/A Other dairy (cottage cheese, cream cheese, sour cream)* N/A N/A Buttermilk** Sour cream** Cream cheese** Cottage cheese** Please refer to pages of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating

3 MEAT / POULTRY / SEAFOOD Overall Female Male Spring Summer Fall Winter Ground beef Other beef (steak) Meat from Hunting, private kill, live animal market, butcher shop N/A N/A Chicken ground) Stuffed chicken N/A N/A product Turkey ground) Pork (ham, bacon) Lamb Sausage Other N/A N/A meat/poultry Fish Shrimp* Other seafood* N/A N/A Shellfish** N/A N/A Please refer to pages of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating FROZEN FOODS Overall Female Male Spring Summer Fall Winter Frozen dinners/entrees* Frozen pizza* Other frozen microwaveable foods* N/A N/A Please refer to page 25 of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating form or population survey may include additional details.

4 FRUITS Overall Female Male Spring Summer Fall Winter Oranges Other citrus (grapefruit, lemon, lime, tangerine) N/A N/A Pears Apples Other tree fruit (apricot, plum, nectarine, peach) N/A N/A Strawberries Other berries (blue, black, raspberries) N/A N/A Grapes N/A N/A Bananas Watermelon Cantaloupe Honeydew or other melon* Other fruit (pomegranate, kiwi, mango, pineapple) Unpasteurized apple cider Other unpasteurized juice N/A N/A N/A N/A Other juice* N/A N/A Please refer to pages of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating

5 VEGETABLES Overall Female Male Spring Summer Fall Winter Prepackaged salad Iceberg Romaine* Leaf lettuce** N/A N/A Salad greens** N/A N/A Other lettuce/leafy N/A N/A greens (red leaf, radicchio, mesclun, endive)* Spinach Cabbage Tomatoes Cucumbers Peppers (green, N/A N/A yellow, red, jalapeno, serrano) Asparagus Celery Carrots N/A N/A Radishes N/A N/A Pea pods/snap peas N/A N/A Onions (red, white, yellow) Green onions/scallions Broccoli Cauliflower* Sprouts (alfalfa, bean, N/A N/A radish, clover)* Micro greens* N/A N/A Cilantro/parsley* N/A N/A Other fresh herbs N/A N/A (basil, thyme, mint, sage) Other vegetables* N/A N/A Egg Plant or Squash** N/A N/A Jicama** N/A N/A Please refer to pages 7-10 of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating

6 OTHER Overall Female Male Spring Summer Fall Winter Mushrooms Tofu Hummus or tahini N/A N/A Nuts (almonds, pecans, walnuts, peanuts, cashews) N/A N/A Sesame seeds* N/A N/A Other seeds (flax, sunflower, alfalfa)* N/A N/A Bean-type snacks (soybeans, garbanzo beans, corn nuts, chickpeas, fava beans, wasabi peas)* N/A N/A Salsa Avocado* Recently purchased spices (black pepper, white pepper, paprika, oregano, cumin)* N/A N/A Spice rubs or N/A N/A blends* Peanut butter Chocolate N/A N/A Trail mix* N/A N/A Chips, crackers, snack foods* Nutritional supplements* N/A N/A N/A N/A Please refer to pages 7-10 of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating

7 RESTAURANTS (Note: Cases were not asked specifically about these restaurants by name. Cases were asked if they ate at a restaurant in the 7 days prior to illness onset. If the case reported eating at a restaurant, the case was asked to name the restaurant.) Restaurant Name Denominator Overall Female Male Spring Summer Fall Winter Applebee s Arby s Burger King Buffalo Wild Wings Chili s Chipotle Culver s Dairy Queen Denny s Domino s Pizza IHOP Jimmy John s KFC McDonalds Noodles and Company Old Country Buffet Olive Garden Outback Steakhouse Papa John s Pizza Panera Perkins Pizza Hut eye s Subway Taco Bell Taco John s Red Lobster Wendy s Please refer to page 26 of the FoodNet ulation Atlas of Exposures, The population survey did not include restaurant names but does have data of types of foods consumed at commercial establishments.

8 OTHER NON-FOOD TRANSMISSION ROUTES Exposure Denominator Overall Female Male Spring Summer Fall Winter International Travel Ill contact before onset Well water* Raw or Untreated water** Other water (such as from a stream while camping)* Recreational water (swim in ocean, lake, river, or pool) Live on Farm* Work on Farm* Visit Farm* Visit petting zoo, educational exhibit, fair or other venue with animals* Cow (present)* Cow (contact)* Goat (present)* Goat (contact)* Sheep (present)* Sheep (contact)* Pig (present)* Pig (contact)* Chicken (present)* Chicken (contact)* Turkey (present)* Turkey (contact)* Please refer to pages of the FoodNet ulation Atlas of Exposures, Question asked by population survey may not have been compatible to hypothesis generating * Question added in 2011 (data only available for ) ** Question removed in 2011 (data only available for )

9 Technical Details Exposure frequencies were calculated from E. coli O157:H7 case interviews from One thousand eight hundred and thirty-three laboratory confirmed E. coli O157:H7 cases were identified during that time period. One hundred and five (7) cases were excluded because they were not interviewed. Two hundred ninety-nine cases that were determined to be part of a recognized outbreak were excluded. One hundred and nine cases who reported international travel within the week prior to their illness onset were also excluded. This left one thousand two hundred and eighty-four cases which were included. However, for each specific exposure if the case did not answer the question they were not included in the denominator for that exposure. Additionally, cases who reported may have eaten were only included in the column, Overall. The questionnaire administered to E. coli O157:H7 cases was modified in Food exposure questions that were added to the interview questionnaire are indicated by an asterisk (*). Food exposures questions that were removed from the questionnaire in 2011 are indicated by a double asterisk (**).