Major improvements in mortality occurred during the 19th century in concert with improvements in hygiene and health hardware infrastructure (11). The broad conclusions from this period are consistent with the large number of hygiene and health studies performed in low-income countries and other disadvantaged populations. In 1983 Blum and Feachem published a review of studies examining the impact of water and sanitation on diarrheal disease. They found methodological problems with all studies but the review still showed a consistent and substantial effect on disease rates (12). A comprehensive systematic review in 2005 again found a substantial reduction in diarrheal disease by water and sanitation projects (13). While the evidence for sanitation and hygiene interventions is strongest in diarrheal disease, there are data for its importance in many infectious diseases of childhood.
In the early 20th century there was considerable interest and publication on housing in the medical literature (14,15,16,17,18). None of this work involved controlled trial interventions but its strength was trying to define the problems with housing for the poor and a focus on change.
Particularly in the last 30 years studies have also emphasised the deleterious mental health effects of poor housing. In a cohort study with 33 year follow up, Marsh et al concluded that poor housing in childhood leads to poorer mental and physical health in later life. They also reported a ‘dose-response effect’. (19). Another more recent cohort study also found that the adverse health consequences of poor childhood housing were independent of socio-economic status (20).
In a systematic review of the relationship between housing and health Thompson et al. reviewed the literature from 1887 to 2000 (21). Reflecting the major methodological, logistic and ethical difficulties in such work they found only 11 prospective studies and only 6 of these with a control group. Their conclusion is likely to apply to work in Indigenous communities,
“many studies showed health gain but small study population and a lack of control for confounders limits generalisability”
A further area of evidence relevant to this work is the importance of maternal practice in both the antenatal period and the first 2 years of life. David Olds has performed 3 randomised controlled trials of a nurse home visiting intervention in the antenatal period and the first 2 years of life (22). The target population were women who were young, single and first time mothers. These interventions produced significant reductions in accidents and emergency department presentations for children . It seems probable that improving the functioning and the safety of the house environment would facilitate improved maternal practice for such mothers. In addition these studies also provide additional evidence that ‘control’ and ‘mastery’ are key issues for health status.
There is a major body of work now emphasising the importance of control and mastery in influencing both physical and mental health (see Ref.23 for excellent summary). The foundational Whitehall studies by Marmot (24) established that ‘lack of control’ in a persons work environment is associated with increased mortality. While this effect exists across social class, it has a strong association with socioeconomic status. There is increasing evidence that control/mastery are factors which may mediate the negative effect of low socio economic (25) status on health as well as acting as an independent driver of health outcomes. There is also some evidence that the importance of control and mastery exists across age groups (26,27))