Research

This section of Gulliver.MD archives a selection of his published research. 

Dr. Gulliver authored or co-authored 215 journal articles, which have been cited 8,849 times (as of September 2025.) 

His ResearchGate profile and complete list of publications are linked here.

A selection of his research indexed by PubMed is linked here. 

A synopsis and discussion of his landmark 1999 publication, Search for the psoriasis susceptibility gene: the Newfoundland Study is here. 

Click here for a summary of An Integrated Analysis of the PIONEER I & II Trials. 

Commentary, summaries, and full text of his articles will be added to this section regularly.

Date: October 26, 2023

Subject: Analysis of Psoriasis Prevalence and Incidence in Newfoundland and Labrador (NL)

Source: Excerpts from "POSTER FINAL NL GPA PDF.pdf"

1. Introduction and Background

• Unique Population: Newfoundland and Labrador (NL) is a geographically isolated Canadian province with a population of approximately 540,000 people. The province's founder population, established between 1780 and 1830, consisted primarily of Irish Catholics and English Protestants. This unique genetic background has made NL a valuable location for studying genetic diseases, specifically psoriasis.

• Early Observations: Initial observations in the early 1990s, in collaboration with Dr. Eugene Farber (Stanford University), highlighted a high prevalence of familial psoriasis within NL, with "documented rates of family history exceeding greater than 80%".

• High Comorbidity Rates: Early studies also reported increased rates of co-morbidities in the NL population, including cardiovascular disease, diabetes, psoriatic arthritis, premature death, and decreased longevity, alongside a high prevalence of psoriasis.

• Past Contributions: This population has significantly contributed to psoriasis research, including the development of new therapies, international genetic collaborations that have led to the discovery of new susceptibility genes, and identifying potential drug targets.

• Study Motivation: Despite anecdotal evidence of a high psoriasis burden in NL, formal studies on the province's incidence and prevalence rates were lacking, thus motivating the present study.

2. Study Objectives and Methods

• Objective: The study aimed to investigate the incidence and prevalence rates of psoriasis in NL, analyzing variations by age, gender, geographic region, and time (2001-2020).

• Data Source: Provincial Electronic Health Records from Digital Health, Newfoundland and Labrador Health Services were used to identify psoriasis patients using the ICD-9 code 696. Data was collected from 2001 to 2020.

3. Key Findings

• Prevalence: The overall prevalence of psoriasis in NL was found to be 6.89% (35,956 individuals with psoriasis out of a 2020 population of 521,359), or 6,830 per 100,000 people.

• This prevalence was seen in 3,801 women and 3,029 men with psoriasis.

• Incidence: The incidence of psoriasis was:

• 365.4 per 100,000 person-years in women (95% CI: 298.0-432.9)

• 334.2 per 100,000 person-years in men (95% CI: 263.5-404.9)

• 395.9 was the overall rate, given by 100,000 person years (329.5-462.2)

• The peak age group for new (incident) cases was 55-59 years. This is noteworthy as late onset of psoriasis is higher than in other populations.

• Geographic Variation: There was significant geographical variation in psoriasis prevalence across NL.

• The majority of communities had prevalence rates between 0-3%.

• A concerning 9 communities with psoriasis prevalence rates over 30% were identified.

4. Discussion and Summary

• High Prevalence and Incidence: The study confirms that the Newfoundland and Labrador population has a high incidence and prevalence of psoriasis, significantly exceeding what is generally seen in other populations.

• Regional Founder Effects: The high prevalence in certain communities can be partially attributed to a regional founder effect, meaning that the original population had a higher incidence than the general population and thus passed on this high risk through successive generations.

• Environmental Factors: The high regional variation in prevalence suggests that environmental influences might also play a role, although these are yet to be fully understood.

• Late-Onset: The study also shows a higher late-onset of psoriasis in this population compared to others, which needs further research.

• Future Research Directions: The authors suggest the data could be combined with other findings to further explore, "gene to gene interactions, climate change, and social determinants health that may influence the onset and the natural history of psoriasis". They express the intent to further understand the complexities of psoriasis through scientific advancements in genetics, population data, and AI.

5. Conclusion

The research confirms that psoriasis is a significant health concern in Newfoundland and Labrador. The province exhibits a high incidence and prevalence, with notable variations across different geographic regions. This highlights the unique genetic and possibly environmental factors that contribute to the disease within the province. Further investigation is warranted to better understand these factors and improve patient care.

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