Table 5

Previous literature on the association between socioeconomic status and coeliac disease

	Geographic area	Study population	Source of the outcome N=number of cases	Source of socioeconomic status	Main findings
Diagnosed CD (serology and/or biopsy-positive cases) within medical settings
Burger et al12	Netherlands	Subjects identified into the Dutch Pathology Registry, which covers all pathology labs in Netherlands 1995–2010 N= 6444	CD diagnosis according to biopsy reports N=4014	The socioeconomic status scores based on income, level of education and employment	Patients diagnosed with CD during childhood were more often from an area with a higher socioeconomic status compared with patients diagnosed later in life (p<0.001)
West et al13	The UK	All ages UK population registered with the Clinical Practice Research Datalink—1990–2011 N=65 856 848 person-years	People with Read codes representing CD (J690.00; J690.13; J690z00; J690100; J690.14; J690000) N=9087	Indices of Multiple Deprivation	The CD incidence was 27% lower in people from the most-deprived areas than in people from the least-deprived ones (IRR 0.83, 95% CI 0.77 to 0.89)
Whyte et al14	Cardiff, Newport and Powys (South Wales)	The total paediatric population (age <16) in South Wales (UK national census 2008) N=298 530 children	CD diagnosis according to ESPGHAN 1990 criteria in the same tertiary medical centre between 1995 and 2012 N=232	Welsh Index of Multiple Deprivation	The prevalence of CD in the lowest deprivation level was 1.16/1000 and 0.49/1000 in the highest deprivation level
White et al15	Southeast Scotland	The total paediatric population (age <16) in Southeast Scotland—1990–2009 (Scotland census) N=∼225 000 children	CD diagnosis according to ESPGHAN 1990 criteria. Data from hospital records (ICD codes of CD), paediatric pathology records, regional clinical database, regional serology database and the electronic hospital record N=266	The Scottish government data for the Standard Index of Multiple Deprivation and urban/rural indices	The median of the Standard Index of Multiple Deprivation score and urban–rural classification indices of patients with CD were comparable to the general population of southeastern Scotland
Olén et al16	Sweden	Individuals aged 16–64 years using the Total Population Register 1969–2008 N=174 186 subjects	CD diagnosis according to biopsy reports collected from all Swedish pathology departments N=29 096	European Socioeconomic Classification based on occupation. Data collected using The Swedish Occupational Register	Individuals from the lowest social class were 11% less likely to be diagnosed with CD (OR 0.89, 95% CI 0.84 to 0.94)
Wingren et al17	Sweden	Prospective evaluation of babies born in Sweden between 1987 and 1993 (follow-up 2 years) N=392 568 men and 372 112 women	The Swedish National Hospital Discharge Registry according to ICD codes of CD N=845 in men and 1401 in women	Information on the mothers’ pre-tax equalised household income and social allowance for the year before delivery (five classes)	Boys born to mothers in an overt low socioeconomic position had a higher risk of CD (OR 1.37, 95% CI 1.03 to 1.82) than those with mothers with high income and no social allowance
Robert et al18	South East England	Babies born in the south east of England between 1970 and 1999 (mean follow-up duration 18 years) using the Oxford record linkage study database having linked maternity data in the same dataset N=248 521	Children with both a maternity record and a subsequent admission for CD (ICD codes of CD) in the Oxford record linkage study database N=90	Information collected from maternal records in the Oxford record linkage study database	Children from manual social classes IV and V had a 4.02 increased risk of coeliac disease (95% CI1.96 to 8.25) compared with those from professional social classes I and II
Ludvigsson19	Sweden	Babies born in southeast Sweden between 1997 and 1999 (follow-up 15 years) N=15 875 single births	Coeliac cases reported by eight paediatric departments A case was included if he had intestinal biopsy suggesting CD, no symptoms after the introduction of a gluten-free diet and/or no or only minor histopathological abnormalities consistent with CD at the control biopsy under treatment with gluten-free diet N=45	Information collected in questionnaire completed by the mothers shortly after childbirth on: place of living 1 year before conception, maternal employed during pregnancy, paternal employed the year before the conception, family crowed living	CD was less common in mothers who had worked <3 months during pregnancy (OR=0.29; 95% CI 0.09 to 0.94; p=0.039). The other socioeconomic factors were not associated
Screening detected CD in the general population
Kondrashova et al20	Finland and Russia	Schoolchildren Russia Karelia: age ranged 6.2–18.3 years (1997–2001) N=1988 children Northern Finland: age ranged 7–18 years (1994) N= 3654 children	Serological screening by tTGA All subjects who were positive were offered an intestinal biopsy to confirm CD diagnosis. N=4 in Russia and 34 in Finland	Comparison between two areas with opposite socioeconomic condition (poor Russia vs rich Finland).	0.6% of the children (12/1988; CI 0.3% to 1.1%) in Russian Karelia tested positive for tTGA compared with 1.4% (52/3654; CI 1.1% to 1.9%) in the Finnish cohort. Biopsy-proven CD: N=4 in Russia and 34 in Finland (no biopsy in 13 subjects)
West et al21	Cambridge	Participants, age 45–76 years registered with a general practice in Cambridge, England (1990–1995) N=7527	Serological screening by EMA N=87	Participant-reported occupation categorised as professional, skilled, unskilled/partly skilled	EMA positivity less common in partly skilled or unskilled workers, as compared to professionals (OR 0.51, 95% CI 0.18 to 1.43)

CD, coeliac disease; EMA, antiendomisial antibody; ESPGHAN, European Society of Paediatric Gastroenterology, Hepatology and Nutrition; ICD, international classification of disease; IRR, incident rate ratio; tTGA, IgA antitransglutaminase.