**1. Introduction**

Internationally suicide is the second leading cause of mortality in young men after accidental deaths [1]. Mortality indicators such as potential years of life lost (PYLL) demonstrate the economic and social cost of suicide in young men, which has become a serious public health problem over the last 70 years [1]. Despite widespread international recognition of the problem [1], and growing media concern, research is lacking on the mediators of suicide risk in young men and the interventions to mitigate them. International studies sugges<sup>t</sup> that individual-level risk factors for suicide in men include psychiatric illness, substance misuse, lower socioeconomic status, rural residence, and single marital status [1]. However, there is a clear need for epidemiological studies of young men in specific regions, to understand the local sociocultural influences on their suicide risk, and the development of appropriate responses. The suicide rate in Arctic communities is considered a major public health concern [2], particularly in adolescents and young men [3]. Indigenous communities in the circumpolar north face a range of geocultural and economic hardships, including the challenges of inadequate housing and access to health care, in the context of global forces eroding local traditions [2]. Greenland has attracted particular media concern over suicide rates in young men, but few epidemiological studies have described this problem. A large (2,150,000 km2) and remote island near the continent of North America, Greenland is a former colony of Denmark, largely populated by Inuit people [4]. According to suicide data published by Statistics Greenland, suicide accounts for 8% of total deaths in Greenland and is the leading cause of death among young men aged 15–29 [5]. However, due to its territorial status, Greenland's suicide rates are subsumed within those for Denmark, such that international rankings mask the problem. Broad comparison of the population suicide rates published by Statistics Greenland for 2011 (83 per 100,000) [5] greatly exceed those published by the World Health Organisation (WHO) for Guyana, the country with the highest population suicide rates internationally that year (32.5 per 100,000) [6], or for the 2015 global average of 10.7 per 100,000 [7]. International comparisons of suicide rates in young men identify particularly high rates in Eastern Europe and Japan, suggesting that suicide risk is higher for young men in countries undergoing transition or rapid social change [8]. Societies in transition experience changes in cultural norms, family cohesion, economic pressures, substance use, and migration patterns. The complex interaction of these variables requires investigation at the local level.

Greenland proposed a Greenlandic suicide prevention strategy in 2004, identifying young men as a high risk group, but acknowledging a lack of research into the aetiology of suicide in this group [9]. Although suicide prevention was included in the 2007–2012 Greenlandic public health programme, it was omitted in the 2013–2019 version [10]. However, Greenland participates in a US-led 2015 Arctic Council project, RISING SUN (Reducing the Incidence of Suicide in Indigenous Groups: Strengths United through Networks) to share expertise in suicide prevention in Arctic communities [2]. The success of such policy efforts relies in part on having a clear understanding of the problem epidemiologically. Suicide data collection in Greenland has a broken history, and policy-makers lack a clear picture of recent trends and high-risk groups. The earliest systematic suicide data collection in Greenland was by one physician from 1891–1930 [11], but there is then a gap until 1951 when annual reports by the country's Chief Medical Officer commenced [12]. Whilst actual numbers of suicides are published by Statistics Greenland for 1990–2013 [5], comparison of patterns with other Arctic areas is difficult without clear presentation of rates, both temporally and by age group. To inform future Greenlandic suicide prevention strategies and highlight gaps in evidence, it is important to understand how suicide rates in young men in Greenland compare with those for young men in Denmark, and with men in other age groups in Greenland.

We aimed to conduct a systematic review of research studies describing the epidemiology of suicide in young men (aged 15–29) in Greenland compared with young men in Denmark, and Greenlandic men in other age groups, using international evidence published up until 2018. In synthesising these findings we aimed to test the hypothesis that suicide rates in young men in Greenland are greater than those for these other groups. Our objectives were to describe historic and recent temporal trends in suicide rates in young men, comparing rates with those for other age and gender groups within Greenland and with other young men in Denmark, and identifying specific risk factors for suicide in young men. In conducting our review we identified a dramatic rise in suicide rates in Greenlandic men aged 15–24 from 1976, such that young men supplanted older men as the highest-risk demographic group for suicide over the period 1976–2011. Our search criteria did not identify any studies describing suicide epidemiology in young men from 2011 onwards, nor specific risk factors for suicide at any point, so recent patterns remain unclear.
