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Impacts of Food Hypersensitivities on Quality of Life in the UK and Willingness to Pay (WTP) to remove those impacts

Appendix H: Sample Descriptives: Demographics and Food Hypersensitivity

Information about the sample demographic, the sample method and descriptives.

Last updated: 15 December 2022
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Last updated: 15 December 2022
See all updates

A sample of 2276 adults was achieved, comprising people who either 

  • have one or more Food Hypersensitivity, or 
  • are a parent/carer of one or more children with a Food Hypersensitivity (FHS).

The sample was recruited in July-November 2021.

The survey sources are:

  • people who completed a survey as part of Workstream 1 of this project and agreed to be recontacted
  • a market research commercial sample recruited from Pureprofile
  • people recruited from marketing / publicity distributed by support groups (Anaphylaxis UK, etc).

The sample was reduced to 2142 after removal of people who completed the survey excessively quickly (an issue most common in the purchased sample).

We now summarise the characteristics of the Adult and then Parents sample.

Demographic Information: Adult sample

The adult sample is now described, first in terms of demographics, and then in terms of their food hypersensitivity.

Sex: The sample was overwhelmingly (77%) female.

Table 1. Tabulation of sex 

Sex Frequency Percent
Male 326 22.89
Female 1098 77.11
Total 1424 100.00

Age: The modal age category was 35 to 54 years old. 

Table 2: Tabulation of age category

Age Frequency Percent Cumulative
Below 35 years old 245 17.24 17.24
35 to 54 years old 462 32.51 49.75
55 to 64 years old 372 26.18 75.93
65 years old and above 342 24.07 100.00
Total 1421 100.00 -

The mean age was 52 years, and the median age of respondents was 55 years old with ages distributed between 17 and 90 years. 

Table 3: Adult age statistics

- Mean Std Dev N Min p25 Median p75 max
Age 52.36 15.68 1421 17 41 55 64 90

Figure 1: Age Distribution Analysis

Tables explain the data in full.

Income: For those who stated their income, the modal income category is £25,000-£34,999 but nearly 20% of respondents refused to state their income.

Figure 2: Income distribution, Adults

Tables explain the data in full.

Distribution of Food Hypersensitivities: Adult sample

Accounting for Multiple Conditions

Just over a third of the sample reported having a food allergy, over 40% reported having coeliac disease or a food intolerance. The distribution of conditions shown (with percent values summing to more than 100) reflect that some people reported having more than one condition. The sample included people with a clinical diagnosis and those whose condition was self-assessed.

Table 4. Distribution of food hypersensitivity Conditions, adults

Food hypersensitivity conditions Frequency Percent
Food Allergy 495 34.7
Coeliac Disease 630 44.2
Food Intolerance 607 42.6
Total 1426 100

Decomposing these figures into single and multiple conditions gives:

Table 5. Distribution of food hypersensitivity Conditions accounting for multiple conditions, adults

Food hypersensitivity conditions Frequency Percent Cum.
Food Allergy 274 19.21 19.21
Coeliac Disease 508 35.62 54.84
Food intolerance 365 25.60 80.43
Multiple 279 19.57 100.00
Total 1426 100.00 -

Figure 3: Distribution of conditions, including multiple conditions, adults

Details explained in the text.

The specific combinations of conditions are shown in Table 9.6 which indicates only 1.9% of respondents report having all 3 conditions, and 18% of respondents report having 2 conditions.

Table 6. Tabulation of food hypersensitivity conditions and combinations 

Food hypersensitivity conditions Frequency Percent Cum.
Food Allergy 274 19.21 19.21
Coeliac Disease 508 35.62 54.84
Food intolerance 365 25.60 80.43
Allergy and Coeliac 37 2.59 83.03
Allergy and intolerance 157 11.01 94.04
Coeliac and intolerance 58 4.07 98.11
Allergy, coeliac and intolerance 27 1.89 100.00
Total 1426 100.00 -

Figure 4: Distribution of conditions, including specific multiple conditions, adults

Tables explain the data in full.

The distribution of conditions by sex is shown here, with 40% of males report having coeliac disease whereas 45% of females report having coeliac disease. Coeliac disease is the most commonly reported condition among both male and female adults, food allergy is the least common condition in both groups. Note that people reporting multiple conditions means these percentage values do not sum to 100.

Table 7: Tabulation of food hypersensitivity conditions by sex 

Female mean sd
Food Allergy 34.8 .48
Coeliac 45.4 .5
Food Intolerance 43.8 .5

 

Male mean sd
Food Allergy 34.7 .48
Coeliac 39.6 .49
Food Intolerance 38.7 .49

Figure 5: Distribution of conditions, by sex

Tables explain the data in full.

40% of males report having coeliac disease whereas 45% of females report doing so. 

The distributions of the 3 conditions between the 4 age groups we use to disaggregate the data are shown in Figure 6.  (Singh et al’s 2018 meta-analysis reports that biopsy-confirmed coeliac disease is 1.5 times more common in females than in males).

Figure 6: Distribution of conditions by age

Tables explain the data in full.

Multiple conditions are much less commonly reported in those aged 65 and over (22% compared to 27-29% of the other groups). Food allergies are relatively uncommon amongst the 65 plus group: 14% of over 65s have only a food allergy whereas 32% of under 35s do so.

Pearson's chi-squared tests indicate that the distributions of conditions are different at the 1% level across age brackets (χ_9^2= 62.5956, Pr = 0.000). Therefore, the null hypothesis of no difference is rejected. 

Identifying the ‘worst’ condition for those with multiple FHS

Twenty percent of the adult sample reported having more than one food hypersensitivity. The tabulations of those conditions, for people’s only or worst condition are shown here – where the sample size is 1426 and the percentage values sum to 100 as each person indicates only a single food hypersensitivity.

Table 8. Tabulation of food hypersensitivity worst or only condition
 

Food hypersensitivity condition Frequency Percent Cum.
Food Allergy 385 27.00 27.00
Coeliac Disease 601 42.15 69.14
Food Intolerance 440 30.86 100.00
Total 1426 100.00 -

Figure 7: Distribution of worst or only condition, adults

Tables explain the data in full.

Coeliac disease was the condition most commonly (by 42%) identified as only/worst food hypersensitivity, just under a third reported food intolerance as only/worst FHS condition, and 27% indicated this was true of food allergy.

Distribution of only or worst condition

The distribution of these conditions between male and female respondents is shown here.

Table 9: Distribution of worst or only food hypersensitivity, by sex

Only or Worst condition Number in each sex: Male (%) Number in each sex: Female (%) Number in each sex: Total (%)
Frequencies: Food Allergy 96 289 385
Cell percentages: Food Allergy 6.74 20.29 27.04

Frequencies: Coeliac Disease

124 475 599
Cell percentages: Coeliac Disease 8.71 33.36 42.06
Frequencies: Food Intolerance 106 334 440
Cell percentages: Food Intolerance 7.44 23.46 30.90
Frequencies: total 326 1098 1424
Cell percentages: total 22.89 77.11 100.00

38% of Males say that coeliac disease affects them the most, whereas 43% of Females do so. 

Pearson's chi-squared tests (Pearson chi2(2) =   2.8974   Pr = 0.235)) indicate that the distributions of worst conditions are not statistically different across sex. 

Figure 8: Distribution of worst or only condition, by sex, adults

Tables explain the data in full.

The distribution of these conditions by age group is shown in Table 10 and Figure 9. 

Table 10: Distribution of worst or only food hypersensitivity, by age

Only or Worst condition Below 35 years old 35 to 54 years old 55 to 64 years old  65 years old and above  Total
Frequencies: Food Allergy 104 140 71 69 384
Cell percentages: Food Allergy 42.45 303.30 19.09 20.18 27.02

Frequencies: Coeliac Disease

79 164 177 180 600
Cell percentages: Coeliac Disease 32.24 35.50 47.58 52.63 42.22
Frequencies: Food Intolerance 62 158 124 93 437
Cell percentages: Food Intolerance 25.31 34.20 33.33 27.19 30.75
Frequencies: total 245 462 372 342 1421
Cell percentages: total 100.00 100.00 100.00 100.00 100.00

Pearson chi2(6) = 66.4119   Pr = 0.000

Figure 9. Distribution of Worst or Only Condition, by age group, Adults 

Tables explain the data in full.

Sampled adults below 35 are most likely to report food allergy as their only (or worst) FHS, whereas people aged over 55 are much less likely to do so; about half of the sample over 55 report Coeliac coeliac Disease disease as their only or worst condition. Those recruited with food intolerances are more evenly distributed across the age groups.

These results are consistent with Coeliac coeliac disease tending to be diagnosed later in life (often at 40-50 years of age) (Paez et al (2017); Zipser et al (2003); Ludvigsson et al (2014)). Care must be taken not to over-interpret these distributions. The sample includes many people with multiple FHS – for them it could be that the symptoms of their multiple conditions differ as they age, it could be that they adapt better to one than the other. Pearson's chi-squared tests indicate that the distributions of only/worst conditions are different at the 1% level across age groups (χ_6^2= 66.4119, Pr = 0.000); the null hypothesis of no difference is rejected. 

Demographic Information: Child Sample

The child sample is now described, first in terms of child and parent demographics, and then in terms of the children’s food hypersensitivity.

Child Age

The children were aged between1 and 17 years old with a mean age of 8.7 years.

Table 11. Summary statistics: child age

- Mean Std. Dev N Min p25 Median p75 max
Age 8.66 4.72 716 1 5 8 13 17

The median age of the children that parents responded about was 8 years old.

Figure 10 Distribution of Child age

Details explained in the text.

Parental income

For those who stated their income, the modal (household) income category is £55,000-£74,999 but it should be noted that 12% of respondents declined to state their household income.

Table 12. Tabulation of income, parents

Income Frequency Percent Cumulative
Below £6,000 18 2.51 2.51
£6,500 to £11,499 35 4.89 7.4
£11,500 to £17,499 21 2.93 10.34
£17,500 to £24,999 48 6.7 17.04
£25,000 to £34,999 88 12.29 29.33
£35,000 to £44,999 66 9.22 38.55
£45,000 to £54,999 70 9.78 48.32
£55,00 to £74,999 115 16.06 64.39
£75,000 to £99,999 80 11.17 75.56
£75,000 to £99,999 33 4.61 80.17
£75,000 to £99,999 19 2.65 82.82
£150,00 to £199,999 21 2.93 85.75
More than £150,000 to £199,999 16 2.23 87.99
Prefer not to say 86 12.01 100
Total 716 100.00 -

Figure 11: Distribution of income, child sample

Tables explain the data in full.

Distribution of Food Hypersensitivities: Child Sample

Accounting for Multiple Child Conditions
Just over 70% the sample reported their child had a food allergy, 29% reported their child had a food intolerance. The numbers reporting their child had coeliac disease was much lower at 12%.

These data reflect that some people reported having more than one condition

Table 13. Distribution of child conditions

Condition Mean Std. Dev
Food Allergy 72.2 .448
Coeliac Disease 11.9 .3242
Food Intolerance 28.5 .452

Decomposing these figures into single and multiple conditions gives this breakdown with 11% of the sample reporting their child had more than one (??) of the 3 conditions.

Table 14.   Tabulation of child conditions, including multiple conditions  

Food hypersensitivity conditions Frequency Percent Cum.
Food Allergy 440 61.45 61.45
Coeliac Disease 60 8.38 69.83
Food intolerance 135 18.85 88.69
Multiple 81 11.31 100.00
Total 716 100.00 -

Figure 12: Distribution of conditions including multiple conditions, children

Tables explain the data in full.

The specific combinations of child conditions that people report are shown in Table 15. 

Table 15: Tabulation of Children's food hypersensitivity conditions and combinations

Food hypersensitivity Frequency Percent Cumulative
Food Allergy 440 61.45 61.45
Coeliac Disease 60 8.38 69.83
Food Intolerance 135 18.85 88.69
Allergy and Coeliac 12 1.68 90.36
Allergy and Intolerance 56 7.82 98.18
Coeliac and Intolerance 4 0.56 98.74
Allery, Coeliac and Intolerance 9 1.26 100.00
Total 716 100.00 -

Figure 13: Distribution of conditions including specific combinations conditions, children

Tables explain the data in full.

10% of respondents report their child having 2 conditions, and only 1.3% of respondents report their child having all 3 conditions. 

Table 16: Tabulation of number of conditions per child

Number of conditions Frequency Percent Cum.
1 Condition 635 88.69 88.69
2 Conditions 72 10.06 98.74
3 Conditions 9 1.26 100.00
Total 716 100.00 -

Identifying the 'worst' condition for those children with multiple FHS

In the child sample 11% reported their child had more than one food hypersensitivity, and so were asked to indicate which one had the greatest impact on their child’s quality of life. 

The tabulations of those conditions, for people’s only or worst condition are shown here – where the sample size is 716 and the percentage values sum to 100 as each person indicates only a single food hypersensitivity.

Table 17. Distribution of child’s only or worst condition

Type of condition Frequency Percent Cumulative
Food Allergy 496 69.27 69.27
Coeliac Disease 73 10.20 79.47
Food Intolerance 147 20.53 100.00
Total 716 100.00 -

69.3% of respondents say that Food Allergy if their only or worst condition, and only 10% reported that coeliac disease was their child’s only or worst condition.

This is a strong contrast with the adult sample in which coeliac disease was the condition most commonly (42%) identified as only or worst condition.