The Golden Retr iever Lifetime Study: Assessing factors associated with owner compliance after the first year of enrollment (2024)

Abbreviations

AAHA

American Animal Hospital Association

C‐BARQ

Canine Behavioral Assessment and Research Questionnaire

GRLS

Golden Retriever Lifetime Study

OR

odds ratio

95% CI

95% confidence interval

2.1. Overview

All 3044 dogs enrolled in GRLS were included in this study. A logistic regression model was constructed with the primary endpoint being failure to fulfill research obligations at the end of the first year after enrollment in GRLS. Data collected from the owner at the time of enrollment in GRLS were used to examine associations with the outcome of non‐compliance.

2.2. Study design and compliance

Enrollment into GRLS was an owner‐driven process that has been described previously.7 Briefly, owners of Golden retriever dogs less than 2 years of age with at least a 2 generation purebred pedigree who were free from known chronic diseases living in the continental United States were recruited through the Morris Animal Foundation website, social media, and word of mouth. Owners were asked to complete a survey and take their dog to a veterinarian at the time of enrollment and each year after enrollment throughout the dog's lifetime. Contact information collected from the owners included their email and mailing addresses as well as their phone number. No direct questions about the owner were included in the survey, rather the survey contained questions about their dog's health and lifestyle (activity level, sleeping habits, etc.). Additionally, veterinarians were asked to complete an annual survey after each routine visit and submit samples collected at the time of the visit, including blood, urine, hair, toenail clippings, and feces to a biorepository for long‐term storage.7

Owners could begin the annual study processes 90 days before their enrollment anniversary date and had about 6 months after that date to fully complete the requirements. A time‐structured reminder protocol that utilized email, phone, and postcard reminders was employed both in advance of the enrollment anniversary and after the anniversary date if the survey had not been completed. Completion of all study requirements at the initial enrollment visit was a study inclusion criterion. For year 1 after enrollment, dogs were placed into 1 of 4 compliance status categories: open (owner still has opportunity to comply), owner noncompliant (owner did not fulfill any requirements or completed survey only), veterinarian noncompliant (owner was fully compliant, but veterinarian survey had not yet been received), or fully compliant (owner was fully compliant and veterinarian had submitted survey and samples) (Figure ​(Figure1).1). For the purposes of this analysis, owners were considered compliant if the information obtained on their dog was complete (fully compliant) or missing the veterinary survey or sample submission (veterinarian noncompliant). Owners were considered noncompliant if they did not complete the survey or if they did not complete a veterinary visit within the required timeframe (owner noncompliant). Owners in the open category, still within the timeframe to be considered compliant should they fulfill study requirements, were excluded from the analysis. The enrollment period for GRLS occurred between September 2012 and March 2015 and the second visit for each participant occurred between September 2013 and March 2016.

2.3. Data collection and analysis

Data collected at the time of enrollment in GRLS were used for this study. Most variables were analyzed based on individual survey questions (eg, sex, age), but individual behavior‐related questions were combined to form composite scores for behavior variables (eg, owner‐directed aggression). Composite scores were calculated using a method outlined in the Canine Behavioral Assessment and Research Questionnaire (C‐BARQ).11, 12, 13 Lower composite scores were favorable for all behavior variables except trainability. Categorical variables were collapsed to facilitate analysis. Composite behavior scores, activity level, walk frequency, and aerobic activity frequency were dichotomized and sleeping location was categorized (Table ​(Table11).

Variables included in the modeling approach for owner noncompliance were the dog's sex and age at enrollment, geographical region of residence (Northeast, Midwest, Mountain, South, Pacific), dog insurance (yes, no), clinic American Animal Hospital Association (AAHA) status (AAHA member at accredited hospital, AAHA member at nonaccredited hospital, not an AAHA member), number of study dogs enrolled with the same veterinarian, number of study dogs with the same owner, where dog was acquired (breeder, shelter/rescue, pet store, friend/relative or neighbor, via internet or newspaper, other), activity level (very active, less active), primary activity (companion, obedience, show, breeding, agility, hunting, field trials, search and rescue, service, other), where dog spends most time (inside, outside, both), where dog sleeps at night (bedroom on bed, bedroom elsewhere, elsewhere in house, garage, outside), home type (single family, apartment/condo/townhome), travel frequency (assessing if owner traveled with dog for 2 weeks or more within previous 12 months), leash walk frequency (daily or less than daily), aerobic activity frequency (daily or less than daily), professional grooming frequency (more than once per month, 2‐4 times per year, yearly, never), home bathing and/or grooming frequency (more than once per month, 2‐4 times per year, yearly, never), heartworm prevention frequency (assessing if used all year, seasonally, or not at all), flea/tick prevention frequency (assessing if used all year, seasonally, or not at all), rabies 1 year vaccine given in past 12 months (yes, no), rabies 3 year vaccine given in past 12 months (yes, no), no vaccines given (yes, no), and the composite scores for stranger‐directed aggression, owner‐directed aggression, stranger‐directed fear, nonsocial fear, dog‐directed fear and aggression, separation anxiety, attachment behavior, trainability, chasing behavior, excitability, and pain sensitivity.

A logistic regression model was constructed using a backwards, stepwise procedure with commercially available software in order to estimate the odds ratios using owner noncompliance as the outcome of interest (StataCorp. 2013, Stata Statistical Software: Release 13, College Station, TX: StataCorp LP). Univariable logistic regression models were used to screen individual exposure variables and a wide statistical association with the outcome of noncompliance (P ≤ .25) was required for inclusion in the multivariable model. The final multivariable logistic regression model was constructed using a critical α for retention ≤0.05. Excluded variables were reintroduced to the final model to evaluate confounding effects (identified by ≥20% change in parameter estimates). First‐order interaction terms for variables included in the final multivariable model were evaluated. The Pearson chi‐square goodness‐of‐fit test was used to evaluate model fit. Odds ratio (OR) and 95% confidence intervals (95% CI) were calculated using the final multivariable logistic regression model.

3.1. Description of population

The initial GRLS population consisted of 3044 dogs. Nine dogs died during year 1 and were removed from the data set. Thus, there were 3035 dog owners included in this study (Table ​(Table1).1). Of these owners, 2626 (86.5%) dogs were fully compliant at the end of year 1 and 192 (6.3%) dogs were noncompliant. The dog population was approximately evenly distributed between male (50.6%) and female (49.4%), with the majority of dogs sexually intact (62.7%) at the time of enrollment. Dogs ranged in age from 5 to 43 months at the time of enrollment, and 80.7% were under the age of 24 months. The study population was approximately evenly distributed across the 5 regions of the continental United States (Table ​(Table11).

3.2. Logistic regression model

Of the 36 variables analyzed using univariable logistic regression models, 20 exposure variables were included in the initial multivariable model: dog age, region, dog insurance, clinic AAHA status, number of dogs in study under veterinarian, activity level, primary activity, where dog spends most time, where dog sleeps at night, travel frequency, leash walk frequency, professional grooming, home grooming, all year heartworm prevention, all year flea/tick prevention, rabies 1 year vaccine, no vaccines given, owner‐directed aggression, chasing behavior, and excitability (Table ​(Table11).

Variables remaining in the final multivariable model were age at enrollment, where dog spends most time, where dog sleeps at night, home grooming frequency, no vaccines given, and excitability (Table ​(Table2).2). No confounding variables were detected. There was 1 significant interaction term between the variables pertaining to home grooming and/or bathing and vaccination status which was included in the final model. Without the interaction term, home grooming P = .012 [2‐4 times per year (OR: 0.71, 95% CI: 0.51, 0.99), yearly (OR: 0.36, 95% CI: 0.05, 2.75), never (OR: 1.59, 95% CI: 0.98, 2.58), >monthly (reference)] and unvaccinated P = .031 (OR: 1.59, 95% CI: 1.04, 2.41). With the interaction term, home grooming P = .005 [2‐4 times per year (OR: 0.77, 95% CI: 0.55, 1.09), yearly (OR: 0.41, 95% CI: 0.05, 3.16), never (OR: 1.93, 95% CI: 1.17, 3.19), >monthly (reference)] and unvaccinated P = .0041 (OR: 3.72, 95% CI: 1.51, 9.18). Although not included in the final model, the number of dogs enrolled in GRLS with the same veterinarian approached statistical significance (P = .051, OR: 0.92, 95% CI: 0.85, 1.00). The Pearson chi‐square statistic indicated that the model fit the data sufficiently well (X² = 984.62; P‐value = .40).

In the adjusted model, owners of dogs who sleep anywhere other than the owner's bedroom at night had higher odds of being noncompliant at their second study visit than were owners who allowed their dogs to sleep in their bedroom. Owners of dogs who sleep in the garage had nearly 6 times higher odds of being noncompliant (OR: 5.66, 95% CI: 1.89, 16.96) compared to owners of dogs who sleep in the bedroom. Additionally, owners of dogs that are never bathed and/or groomed at home had almost 2 times higher odds of being noncompliant (OR:1.93, 95% CI: 1.17, 3.19) than owners of dogs who are groomed at home at least once a month. Owners of dogs without record of vaccination had nearly 4 times higher odds of being noncompliant with study protocols (OR: 3.72, 95% CI: 1.51, 9.18) than owners of vaccinated dogs. Owners had slightly higher odds of being noncompliant (OR: 1.05, 95% CI: 1.03, 1.07) with each additional month added to their dog's age at the time of enrollment in GRLS. Owners of dogs who spend most of their time both inside and outside had 1.5 times higher odds of being noncompliant (OR: 1.50, 95% CI: 1.09, 2.05) than owners of dogs who spend most time indoors. Finally, owners of dogs who were more excitable (composite score > 1) had nearly 2 times higher odds of being noncompliant (OR: 1.56, 95% CI: 1.07, 2.26) than owners of dogs who were less excitable (composite score 0‐1).

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