joint strategic needs assessment foundation profile - JSNA

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prevalence has increased for between 2007 and 2009 for men and women aged 25-64
years. The reason for this is unknown, but it could be due to random variation and
simply differences in the types of people surveyed 29 . Furthermore, the total number of
people surveyed in the Prevalence Survey 2009 is less than half that of the Health and
Lifestyle Survey 2007, and in some age groups the numbers are relatively small. For
instance, there are fewer than 40 men surveyed who were aged 75+ years.
As the distribution of the age differs among the wards, it is useful to standardise the
percentages for age when comparing the prevalence across the wards. As the number
of survey responders are relatively low in the Prevalence Survey 30 , the prevalence
estimates have been produced for the Prevalence Survey 2009 and Social Capital
Survey 2009 combined (which gives a total of almost 6,000 survey responders). Figure
80, Figure 81 and Figure 82 give the age-adjusted percentages of men, women and
persons who are current smokers for the wards in North, East and West Localities
respectively. The underlying data are given in the APPENDIX on page 859. The 95%
confidence intervals are displayed. For all wards there is considerable overlap in the
confidence intervals for men and women, suggesting that there is no statistically
significant difference in the prevalence of smoking between men and women. However,
there is a statistically significant difference in the prevalence of smoking among the
wards.
If pairs of the 95% confidence intervals do not overlap, then there is a statistically
significant difference in the rates between the two wards. However, if there is only a
small overlap, the difference could still be statistically significant, but further statistical
analysis needs to be undertaken to establish whether this is the case or not 31 .
In North Locality, the prevalence of smoking is significantly lower in King‟s Park,
Beverley and University compared to Bransholme East, Bransholme West and Orchard
Park and Greenwood.
29 Residents were approached to participate in the 2007 and 2009 surveys through the same method
(face-to-face contact at home; knocking on doors), the completion method differed. The majority of the
surveys completed during 2007 were self-completion, with the company undertaking the survey agreeing
with the householder to return at a specific date and time to collect the completed questionnaire, whereas
in the most recent survey, the (shorter) questionnaire was completed by interview. Response rates for
surveys do tend to decrease with increasing social class, and literacy levels are relatively low in Hull, so it
is possible that people in lower social class groups (which include a higher percentage of smokers) were
less likely to participate in the 2007 survey. This may well explain some of the differences found among
the two latest surveys.
30 Especially when examining subgroups by gender, age and Locality (for example, number of men aged
75+ in North Locality is only 10 in the Prevalence Survey).
31 For these comparisons a logistical regression model including age group as a dummy variable has been
used to assess if there is a difference between two wards. Any test examining males and females
combined will not be independent of the test for males or females. Furthermore, even if there were no
differences in the prevalence rates, one would expect 5% of comparisons to be statistically significant due
to chance. Therefore, when comparing a number of wards, it is possible that statistically significant
differences are obtained when there is no underlying real difference.
Joint Strategic Needs Assessment Foundation Profile – Hull Health Profile: Release 3. March 2011. 249