23 Ms C Howell, of counsel, who appeared for the applicant, in summary, made the following oral and written submissions in relation to the medical factors:
1. The rates for shift penalties have remained unchanged and have not been the subject of review or analysis since 1973;
2. Shift allowances fixed by the Shift Workers Case are no longer sufficient for nurses because there had been major developments in the scientific knowledge of both physiological and the psychological effects of shift work and night shift work since 1972 which demonstrate that the allowance set in the Shift Workers Case underestimates the detriment occasioned from working shift work;
3. The Full Bench in the Shift Workers Case had limited evidence of the effects of shiftwork on health and found it was "too indefinite to carry much weight in assessing compensation". The level of medical knowledge is now more extensive and detailed. Additional factors have been identified as to the increased risk of disease and other medical conditions from working night shifts which should be taken into account when fixing the night shift allowance;
4. There was an increased risk of developing adverse health problems and conditions if a certain incidence of night shifts were worked over a certain period of time. In respect to some risks, they become statistically significant after a certain period of time which ranges from five years to 30 years. Key empirical studies have shown that shift workers have a higher risk of developing serious medical problems including cardiovascular disease, breast cancer, gastro-intestinal disorders and reproductive health problems and are, thereby, exposed to the risk of injury to their health and safety. Until the employer can abolish the risk, there is no reason why the risk should not be recognised in remuneration;
5. In particular, the evidence demonstrated the following risks from working night shifts:
(i) There is ample, reliable, expert evidence from Professor Grunstein to show that exposure to circadian disruption and sleep deprivation as a by-product of night or rotating shiftwork poses a significant medical risk. The risk increased with repeated exposure. Nurses working night shifts have reduced sleep hours which lead to a range of medical conditions including diabetes and gastro-intestinal disorders;
(ii) Women who work night shifts have an increased risk of cardiovascular disease. The expert evidence showed there was an increased risk in cardiovascular morbidity for nurses working continuous shift work for six years or more;
(iii) There was a link between working shift work and an increased risk of contracting some forms of cancer. A number of studies showed a higher risk of cancer relating to night work. In particular, one study showed that there was a statistically significant risk after 30 years of night shift. Shiftwork involves circadian disruption and has been ranked on the second tier used to grade carcinogenicity to humans.
6. The ageing workforce makes the issue of night shift particularly significant both from a health and safety and workforce perspective. An increase in the shift allowance would encourage younger nurses to undertake night shift rather than older nurses, causing a redistribution of work with two consequences. First, older nurses would work fewer night shifts and, secondly, there would be a much greater scope for nurses to exercise their own personal preferences for working night shifts. Older nurses, who are most at risk, would have a greater degree of flexibility in the number and configuration of shifts and, thereby, alleviate the chance of longer serving and older workers performing night shift work. It was, therefore, submitted that an increase in the night shift allowance will ameliorate the health risks associated with working night shifts.
24 Mr I Taylor, of counsel, who appeared on behalf of the respondent, made, in summary, the following oral and written submissions:
1. The Department accepted that the knowledge of shift work and its potential to be a risk factor in respect to some medical issues has developed since 1972. It contended, however, that there was not overwhelming evidence of very significant health consequences associated with the performance of shift work. The diseases identified by the medical evidence are relatively uncommon and an increase in risk, although not insignificant, does not mean shift workers will suffer such adverse health outcomes. It was conceded that the significance of the risk increases for nurses who continue to work night shifts over a certain period of time. However, the significance of that risk is to be understood in a context where only a small percentage of nurses will work continuous night shift work for an extended period of time.
2. The Nurses' Association was unable to show that nurses in New South Wales were, in fact, working the requisite pattern of work and, thereby, being exposed to those risks. The Department submitted that Professor Grunstein's expert evidence must be qualified. A number of the variables, which may affect the health risks associated with working nightshifts, were ones that Professor Grunstein could not differentiate because the studies in question did not specifically consider the relationship between the variable and risk. The variables included:
(a) Whether it made a difference if the shifts were rotating shifts or permanent shifts;
(b) The length of the shifts;
(c) The amount of break between shifts and their sequencing;
(d) The age of workers;
(e) The degree or choice over which nurses worked night shifts;
(f) The climate or environment of work; and
(g) The time of day/night that the nightshift worked.
3. The Department accepted that Professor Grunstein's report cited two studies, both of which examined a link between mortality and sleep time. However, these studies did not provide a sound basis to show there was a direct link between short sleep and mortality generally, nor short sleep and cancer or cardiovascular death. The studies tendered by the Nurses' Association, therefore, had little relevance to nurses in New South Wales working night shifts;
4. It was conceded that there is an increased risk of developing cardiovascular morbidity and mortality for nurses working continuous night shifts for six or more years. In oral submissions, it was further conceded that women who work night shifts have an increased multivariate adjusted relative risk in respect of years for cardiovascular mortality. It was also accepted that the length of time engaging in continuous shift work is a significant risk factor for nurses;
5. The Department conceded that some studies showed working continuous night shifts over an extended period might, in some limited circumstances, increased the risk of some forms of cancer. However, studies showed no significant increase in breast cancer, except for those who have worked continuous shift work for over 30 years. As to colorectal cancer and endometrial cancer, any noticeable risk only arose when working continuous shift work over an extended period of time. Again, this risk was only significant after working 15 to 20 years of continuous shift work. Shift work has been listed by the World Health Organisation International Agency for Research as something, which is "probably carcinogenic". It is not placed in group one, which lists agents that have found to be carcinogenic. It has been placed in group two because some studies have found a link between shift work and an increased risk of cancer. Overall, there is inconclusive evidence to demonstrate that nurses working night shifts is a factor which significantly increases the risk of cancer;
6. The Nurses' Association failed to establish or identify any significant health issues arising for nurses working night shifts, in relation to diabetes, weight gain, pregnancy and gastrointestinal disorder.