7. Demographic, socioeconomic and lifestyle factors
7.1 Aims
The aim of this analysis is to:
- present a descriptive profile of the participating men in the Gulf War veteran group and comparison group,
- assess these two study groups for differences in demographic, socioeconomic or smoking or alcohol consumption patterns, which may impact upon the results of the health investigations.
All results in this chapter refer to male participants. The information in relation to female participants is presented in chapter 15. All results for female participants have been presented separately from those of male veterans because the numbers of females are quite small and health patterns in men and women can be quite different. If the data for the female participants was included with the male data, patterns specific to women would be difficult to identify.
7.2 Research questions
1. Are Australian Gulf War veterans similar to the comparison group in relation to demographic factors, including age and ADF service related parameters?
2. Are Australian Gulf War veterans similar to the comparison group in relation to socioeconomic factors, including educational and occupational status?
3. Are Australian Gulf War veterans similar to the comparison group in relation to lifestyle factors, particularly tobacco smoking and alcohol consumption?
7.3 Methods and materials
7.3.1 Subjects
Subjects included in this analysis were all males who completed the self-administered postal questionnaire. These included 1424 Gulf War veterans and 1548 comparison group subjects.
7.3.2 Measurement of demographic and socioeconomic variables
Demographic variables including age, country of birth, indigenous status, language spoken at home and marital status were collected by postal questionnaire.
Information in relation to ADF service type at August 1990, and ADF employment status at time of sampling (serving versus not serving), was provided by the DVA. All other socioeconomic measures, including the ADF-related parameter ‘Rank at Jan 1991’, highest level of education, occupational status, periods of unemployment three months or greater since August 1990, and main source of income were self-reported in the postal questionnaire.
Responses to the parameter “Rank at Jan 1991” were used to categorise subjects in to the following groups:
- Officers: This group included all commissioned officer ranks.
- Other ranks – supervisory: This group included all non-commissioned officer ranks and junior non-commissioned officer ranks. These ranks are considered to hold supervisory positions in the three services. The lowest ranks included, in this category, were Leading Seaman in the Navy, and Corporal in the Army and Air Force.
- Other ranks – non supervisory: This group included the remaining enlisted ranks; Seaman and Able Seaman in the Navy, Private and Lance Corporal in the Army, and Aircraftman/Aircraftwoman and Leading Aircraftman/Aircraftwoman in the Air Force.
7.3.3 Measurement of cigarette smoking and tobacco use
Smoking status and total pack-years of cigarette consumption, for current and former smokers, were derived from responses to a brief set of questions in the postal questionnaire. Participants were categorised in to three ‘smoking status’ categories similar to those used by the Australian 2001 National Drug Strategy Household Survey.[343]
Current smoker: Subject had smoked at least 100 cigarettes in his life-time and currently smoked at least one cigarette per day or one cigar per week or one ounce of tobacco per month.
Former smoker: Subject had smoked at least 100 cigarettes in his life-time, did not currently smoke at least one cigarette per day or one cigar per week or one ounce of tobacco per month, but had smoked as much as this in the past.
Never/occasional smoker: Subject had never smoked as much as one cigarette per day or one cigar per week or one ounce of tobacco per month.
For the purpose of calculating total pack years of cigarette consumption, for current and former smokers, it was necessary to derive the total duration, in years, of cigarette consumption and the average number of cigarette-packs, or equivalent, smoked on each day of those years.
Current and former smokers were asked to report the age at which they first started smoking regularly, and former smokers were asked to report the age at which they stopped smoking regularly. Years of smoking were calculated as the period elapsed between the age of first regular smoking and current age (for current smokers) or age last smoked regularly (for former smokers).
Smokers were asked to provide an estimate of the average number of cigarettes smoked daily, the average number of grams of tobacco smoked daily (not including tobacco from cigarettes or cigars) and the average number of cigars smoked weekly.
The information on years of smoking and average number of cigarettes daily was used to calculate the total number of cigarettes smoked, and this was expressed in pack-years. It was assumed that one pack contained 20 cigarettes, that one cigar was equivalent to three cigarettes 1 and that one gram of tobacco was equivalent to 2 cigarettes 2. Pack-years were calculated as = total cigarettes (or equivalent) ÷ 20 ÷ 365. One pack year is equivalent to smoking one pack of 20 cigarettes per day for a year. A person who smoked an average of 16 cigarettes per day for a duration of 12 years (the equivalent of 70,080 cigarettes) received a pack-years score of 9.6 (70,080 ÷ 20 ÷ 365 = 9.6).
7.3.4 Measurement of alcohol consumption
The pattern and level of alcohol consumption was derived from postal questionnaire responses to the first three questions of the Alcohol Use Disorders Identification Test (AUDIT).[276] These questions covered frequency of alcohol consumption, average number of standard drinks on a typical day when drinking and frequency of drinking six or more alcoholic drinks on one occasion of drinking.
7.4 Results
7.4.1 Demographic and socioeconomic variables
Table 7.1 shows the mean age of male Gulf War veteran and comparison group participants and the numbers and percentages of participants within sub-categories of the various demographic and socioeconomic parameters measured.
It should be noted that the variable ‘age’, in this descriptive table, is age at the time of participation in the study. This is in contrast to the previous Recruitment chapter where age at August 1990 (the time of the start of the Gulf War) was used to compare participants with non-participants.[c] Further, the parameter “Rank in January 1991” reported in Table 7.1 is drawn from postal questionnaire responses, in contrast to the parameter “Rank in August 1990” which was reported in the Recruitment chapter for all participants and non-participants, and which was sourced from DVA records. 3
On average, male Gulf War veterans were approximately one year younger than male comparison group participants, less highly ranked in January 1991 and less likely to have tertiary education. Gulf War veteran Army and Air Force males were less likely to participate than comparison group males of these service types, and Gulf War veteran Navy males were more likely to participate than their comparison group counterparts. These differences reached statistical significance.
Male participants of both groups were equally likely to be born in Australia, to speak English as the main household language, to be married, to be in paid employment and to be sourcing their main income from a wage or own-business. Gulf War veterans and comparison group participants reported similar levels of indigenous origin, however large numbers of subjects in both groups (> 7%) failed to respond to this question. Approximately two thirds of subjects in each group were no longer serving members of the ADF at the time of sampling.
Gulf War veterans were no more likely, than the comparison group, to have sustained a period of unemployment of three months or greater since August 1991. However the Gulf War veteran participants were more likely to report that such a period of unemployment was primarily health related.
| Demographic and socioeconomic parameters |
Gulf War veterans (N=1424) | Comparison group (N=1548) | ||||
|---|---|---|---|---|---|---|
| Mean | (SD) | Mean | (SD) | P value | ||
|
Age at date of participation
|
38.1
|
(6.4)
|
39.3
|
(6.4)
|
<0.001
|
|
| n | (%) | n | (%) | P value | ||
|
Age category at date of participation
|
||||||
| <30 |
114
|
(8.0)
|
62
|
(4.0)
|
 |
<0.001
|
| 30-34 |
413
|
(29.0)
|
386
|
(24.9)
|
||
| 35-44 |
689
|
(48.4)
|
796
|
(51.4)
|
||
| >= 45 |
208
|
(14.6)
|
304
|
(19.6)
|
||
|
Service type at Aug 1990
|
||||||
| Navy |
1232
|
(86.5)
|
1123
|
(72.5)
|
 |
<0.001
|
| Army |
87
|
(6.1)
|
172
|
(11.1)
|
||
| Air Force |
105
|
(7.4)
|
253
|
(16.3)
|
||
|
Rank at Jan 1991
|
||||||
| Officer |
268
|
(18.8)
|
391
|
(25.3)
|
|
<0.001
|
| Other rank-supervisory |
686
|
(48.2)
|
740
|
(47.8)
|
||
| Other rank-non supervisory |
468
|
(32.9)
|
417
|
(26.9)
|
||
|
ADF employment status
|
||||||
| Serving |
605
|
(42.5)
|
624
|
(40.3)
|
 |
0.229
|
| Not-serving |
819
|
(57.5)
|
924
|
(59.7)
|
||
|
Country of birth
|
||||||
| Australia |
1194
|
(83.8)
|
1289
|
(83.3)
|
|
0.589
|
| UK/Ireland |
148
|
(10.4)
|
177
|
(11.4)
|
||
| New Zealand |
14
|
(1.0)
|
20
|
(1.3)
|
||
| Other |
64
|
(4.5)
|
61
|
(3.9)
|
||
|
Aboriginal or Torres Strait Islander
|
||||||
| Yes |
19
|
(1.3)
|
22
|
(1.4)
|
|
0.825
|
| No |
1301
|
(91.4)
|
1405
|
(90.8)
|
||
| Missing |
104
|
(7.3)
|
121
|
(7.8)
|
||
|
Language usually spoken in household
|
||||||
| English |
1406
|
(98.7)
|
1531
|
(98.9)
|
|
0.260
|
| Other |
6
|
(0.4)
|
3
|
(0.2)
|
||
|
Marital status
|
||||||
| Married/defacto |
1080
|
(75.8)
|
1195
|
(77.2)
|
|
0.223
|
| Separated/divorced/widowed |
162
|
(11.4)
|
187
|
(12.1)
|
||
| Single, never married |
171
|
(12.0)
|
156
|
(10.1)
|
||
|
Highest education level
|
||||||
| Up to year 10 |
266
|
(18.7)
|
273
|
(17.6)
|
|
0.002
|
| Years 11 or 12 |
264
|
(18.5)
|
225
|
(14.5)
|
||
| Certificate or Diploma |
694
|
(48.7)
|
772
|
(49.9)
|
||
| Tertiary |
196
|
(13.8)
|
274
|
(17.7)
|
||
|
Occupational status
|
||||||
| Paid employment (FT, PT, self-employed) |
1309
|
(91.9)
|
1440
|
(93)
|
|
0.653
|
| Not working due to ill-health |
29
|
(2.0)
|
26
|
(1.7)
|
||
| Unemployed |
45
|
(3.2)
|
41
|
(2.6)
|
||
| Other (student/volunteer/home-duties/retired) |
39
|
(2.7)
|
37
|
(2.4)
|
||
|
Any period of unemployment more than 3 months since
august 1991
|
||||||
| Yes, primarily due to health problems |
75
|
(5.3)
|
52
|
(3.4)
|
|
0.015
|
| Yes, not primarily due to health problems |
229
|
(16.1)
|
283
|
(18.3)
|
||
| No |
1102
|
(77.4)
|
1202
|
(77.6)
|
||
|
Main income source
|
||||||
| Wage/own business |
1298
|
(91.2)
|
1421
|
(91.8)
|
|
0.356 |
| Disability pension |
22
|
(1.5)
|
20
|
(1.3)
|
||
| Other Govt pension or allowance |
65
|
(4.6)
|
58
|
(3.7)
|
||
| Superannuation/dividends |
29
|
(2.0)
|
43
|
(2.8)
|
||
7.4.2 Cigarette smoking and tobacco use
The breakdown of male Gulf War veteran and comparison group participants according to smoking status, and means and standard deviations (SD) for total pack-years for current smokers and former smokers, are shown in Table 7.2. The proportions of subjects who were categorised as current, former or never/occasional smokers were similar in the two study groups. Gulf War veteran current smokers and former smokers, however, averaged fewer pack-years of smoking when compared with comparison group current smokers and former smokers.
7.4.3 Alcohol consumption
Responses to the alcohol frequency and quantity questions of the AUDIT, for Gulf War veteran and comparison group participants, are presented in Table 7.3. Patterns of alcohol consumption were very similar in the two groups.
| Smoking | Gulf War veterans | Comparison group | ||||
|---|---|---|---|---|---|---|
| n | (%) | n | (%) | P value | ||
|
Smoking status
|
||||||
| Current smoker |
369
|
(25.9)
|
356
|
(23.0)
|
|
0.172
|
| Former smoker |
433
|
(30.4)
|
498
|
(32.2)
|
||
| Never/occasional |
619
|
(43.5)
|
690
|
(44.6)
|
||
|
Cigarette pack years
|
Mean | (SD) | Mean | (SD) | P value | |
| Current smokers |
18.5
|
(14.9)
|
21.6
|
(18.2)
|
0.012
|
|
| Former smokers |
12.6
|
(13.5)
|
14.9
|
(17.8)
|
0.027
|
|
| Alcohol | Gulf War veterans | Comparison group | ||||
|---|---|---|---|---|---|---|
| n | (%) | n | (%) | P value | ||
|
Frequency of taking a drink
|
||||||
| Never |
45
|
(3.2)
|
43
|
(2.8)
|
|
0.901
|
| Once a month or less |
169
|
(11.9)
|
178
|
(11.5)
|
||
| 2 to 4 times per month |
391
|
(27.5)
|
434
|
(28.0)
|
||
| 2 to 3 times per week |
454
|
(31.9)
|
511
|
(33.0)
|
||
| 4 or more times per week |
361
|
(25.4)
|
379
|
(24.5)
|
||
|
Amongst drinkers: number of drinks on a standard
day
|
||||||
| 1 or 2 |
490
|
(35.6)
|
559
|
(37.2)
|
|
0.318
|
| 3 or 4 |
462
|
(33.6)
|
521
|
(34.7)
|
||
| 5 or 6 |
237
|
(17.2)
|
257
|
(17.1)
|
||
| 7 to 9 |
94
|
(6.8)
|
89
|
(5.9)
|
||
| 10 or more |
89
|
(6.5)
|
74
|
(4.9)
|
||
|
Amongst drinkers: frequency of taking 6 drinks or
more on one occasion
|
||||||
| Never |
152
|
(11.1)
|
195
|
(13.0)
|
|
0.181 |
| Less than once a month |
596
|
(43.3)
|
668
|
(44.5)
|
||
| Monthly |
301
|
(21.9)
|
326
|
(21.7)
|
||
| Weekly |
269
|
(19.6)
|
262
|
(17.4)
|
||
| Daily or almost daily |
55
|
(4.0)
|
45
|
(3.0)
|
||
7.5 Discussion
Demographic and socioeconomic parameters such as age, education level and marital status, and lifestyle factors such as smoking and alcohol consumption, are known predictors of health status. Amongst Australian adults younger age has been shown to be related to poorer mental health, as have lower education levels, whilst marriage has been shown to be associated with better mental health.[309] Health problems associated with alcohol consumption include liver damage, cancers, pancreatitis, diabetes and epilepsy. Alcohol is also a significant factor in motor vehicle injuries and fatalities, falls, drowning and suicide. Tobacco smoking has been associated with diseases including cardiovascular diseases, cancers, emphysema, stroke and thrombosis.[346] Differences in the health status of the Gulf War veteran and comparison group participants, unrelated to the deployment to the Gulf War, could result if these two study groups were markedly different in their demographic, socioeconomic and lifestyle patterns.
The comparison of the two groups in this study showed reassuring parallels in current smoking status and alcohol consumption, country of birth, indigenous origin, language spoken at home, marital status, ADF serving status, occupational status and main source of income. There were small differences between the two groups in relation to age, education level and rank at January 1991 and these could exert some confounding influence on the results of health outcome measures. Where possible, these differences will be statistically controlled for when the results of health outcome measures are assessed in the following chapters.
The different service-type pattern between the two groups could also exert some confounding effects upon the study health outcomes. Anecdotal evidence suggests that Army Gulf War veterans, particularly those who deployed with Operation Habitat, may have experienced poorer health than Gulf War veterans of the Navy and Air Force. In addition it would seem likely that Air Force participants, particularly air-crew personnel who are required to maintain a high level of health and fitness, would report improved health when compared with participants from other services. Any confounding effects of service type, however, are likely to be minor considering the relatively small numbers of contributing participants from the Army and Air Force services. Nevertheless, the true effects of service type will be considered carefully in the further analysis of health outcomes in this study.
Patterns of alcohol use could be considered both predictive of ill-health, and also a health outcome in itself. For example, stressful life events can be associated with the subsequent onset of heavy drinking.[347] Therefore, a more thorough investigation of alcohol use and alcohol related disorders will be presented in chapter 11.
Smoking patterns in both groups were very similar to those reported for the Australian male adult population in the 2001 National Drug Strategy Household Survey.[343] The pack-years difference between the two groups may be important and could imply poorer health in the comparison group related to this higher exposure. It must be noted however, that the pack-years estimates were based on years of smoking derived from reports of age first started smoking and year last smoked, with no reports of any remission from smoking for any intervening period. Whilst this method of recording years of smoking is recommended in the Australian National Health Data Dictionary,[348] it is likely to result in an overestimation of total pack-years in both groups.
Study participants were more likely to be Australian born, or British or Irish born, when compared with the average Australian, and more likely to be married.[349] Compared with the national average of 2%, study participants were less likely to be of indigenous origin.[349]however the participation rate in this group is consistent with estimates that the Australian indigenous population comprises approximately 1.2% of total Australians in employment.
More than 40% of all male participants drank “six or more drinks on one occasion” on a monthly or more frequent basis. It is possible that a large proportion of these could be considered as regularly drinking in excess of the Australian NHMRC drinking guidelines for men, which includes the recommendation of “not more than 6 standard drinks in any one day”.[350] Our method of data collection, however, does not allow us to make a direct comparison with the NHMRC guidelines.
In conclusion, male participants in the two study groups were very similar with regard to many of the demographic and socioeconomic measures, and with regard to current smoking status and alcohol consumption patterns. Where differences were found in age, rank and education pattern these were typically small. In general it is unlikely that small differences between the two groups would exert considerable confounding influence upon the results of health investigations in this study. Increased pack year estimates amongst comparison group subjects may be associated with some increased morbidity in this group. However, the true influence of these factors, along with that of other possible confounding exposures unrelated to the Gulf War deployment, will be examined in more detail in subsequent chapters.
7.5.1 Summary of findings
In summary, and in relation to the research questions posed for this chapter:
Australian male Gulf War veterans and comparison group participants were very similar in relation to most demographic, socioeconomic and lifestyle measures, including current smoking status and alcohol consumption, country of birth, indigenous origin, language spoken at home, marital status, ADF serving status, occupational status and main source of income.
There were some differences between the two study groups in age, rank, service type, education and pack years of smoking. Whilst it is unlikely that these small differences will exert considerable confounding influence on the results of the study, where possible, statistical adjustment for these factors will be made.
[1] Estimate based on the American Cancer Society report (344. American Cancer Society. Cigar smoking and cancer: Is cigar smoking on the rise? Atlanta, Georgia: American Cancer Society, 2000.) which indicated that “Most cigars have as much nicotine as several cigarettes”
[2] Estimate based on King & Borland (345. King R, Borland R. The growth of 'low tar' and ventilated filter cigarettes in Australia. Nicotine and Tobacco Research submitted.) who gave the median tobacco weight for Australian cigarettes as 536 milligrams
[3] Wherever possible self reported sources of data are used for the comparison of participating groups in this report. In the recruitment chapter, self reported data was often not available for non-participants, and therefore data sourced from DVA records was often used for comparisons of participants with non-participants.
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