*4.1. Main Findings*

Overall our findings support a pattern of consistently higher suicide rates in young Greenlandic men over the period 1976–2011, both when compared with men in other age groups, same-age Greenlandic women, and with men and women of all age groups in Denmark [21]. Aggregated data for periods over 1970–2011 suggests that men aged 20–24 were the highest risk group for suicide in Greenland, followed by men aged 15–19. Evidence from the narrowest period of reporting in 1990–1995 suggests that men aged 15–19 replaced men aged 20–24 as the group at highest risk around this point, at approximately 480 per 100,000 population [24]. This was also the point at which population rates stabilised, at approximately 110 per 100,000 population until the end of 1995 [24]. However, as the only study reporting rates for single years collapsed both age ranges [20] we cannot pinpoint if and when men aged 15–19 overtook men aged 20–24 as the highest ranking age group for suicide.

At the Greenlandic population level, age-standardised population suicide rates over the period 1972–1995 increased markedly from approximately 44 per 100,000 population in 1975 to approximately 110 per 100,000 in 1984–1989, stabilising at 110 per 100,000 from 1990–1995 [24]. This dramatic rise coincides with a time of high suicide rates in Greenlandic men aged 15–24, [12,18,20,21,23,24] suggesting that this age group accounted for the population-level transition. This apparent shift in suicide rates in Greenland from elderly to younger men matched the transition that occurred from 1950–1999 in some high-income countries [1], as suicide rates rose in middle-aged men (aged 35–45) and in young men (aged 15–25), largely supplanting older men as the group at highest risk of suicide [26]. The studies we identified, however, did not present a fine-grained picture of whether and how this age transition occurred. Variation in the years and age ranges reported also hamper direct comparisons of suicide rates across age groups in Greenland to those in other countries.

Geocultural factors are likely to be relevant in explaining suicide epidemiology in Greenland. Primarily covered by an ice sheet, it is sparsely populated by approximately 57,000 people, mainly Inuit people who started to migrate there from Canada in 2500 BC [4]. Its high latitude, ranging from 59◦ N to 84◦ N, accounts for extreme seasonal variations in daylight and darkness hours. The country has arctic climatic conditions; seasonal temperatures vary with latitude and distance from the coast, but average yearly temperatures remain below 10 ◦C [27]. Its remoteness kept it culturally insulated from its neighbours until the 18th century, but in 1953 its colonial status ended and it became an integrated constituency, governed by the Danish state and giving Greenlanders Danish citizenship [28]. This marked the start of a period of rapid sociocultural and socioeconomic changes under the modernising influence of Denmark. These included a change from subsistence hunting and fishing to a wage-earning economy, the migration of non-Inuit people to Greenland, and increased urbanisation, influencing changes in infrastructure and housing [29]. Genetic studies find that over 80% of Greenlanders have some European ancestry due to recent migration (approximating to 25% of their genome), inherited primarily from male Europeans [4]. In 1979, Greenlanders voted for Home Rule, which gave them the right to elect their own parliament, reducing the influence of Denmark. Greenland gained further autonomy in 2008, when a vote for self-governance was passed by a 75% majority and Home Rule was replaced. Greenlanders are now recognised as separate people under international law, and the native Inuit language of west Greenland has official status in place of Danish. The country has autonomous control over areas such as education, health and environment, whilst Denmark still governs justice affairs, national security, civil rights and financial sectors [28].

These geopolitical factors set important context. The dramatic increase in suicide rates in young men in Greenland in the 1970s coincided with a period of rapid modernisation and social change. However, we were unable to identify specific risk factors for suicide in young men as no studies reported these. We can only therefore hypothesise that specific aspects of modernisation increase risk. Superficially, evidence for regional variation in male suicide rates appears to undermine arguments for the effects of modernisation, given that rates are much higher for men of all ages in rural areas of East and North Greenland than in West Greenland, or the capital, Nuuk [18] and for young men in rural East Greenland from 1968–1999 [21]. However, the explanation may lie in disparities in socioeconomic status between men in urban and remote areas. The problem is that the individual-level suicide risk factors identified for young men in other countries (psychiatric disorder, substance misuse, occupational group, ethnicity, rural residence, lower socioeconomic status, single marital status) have not been specifically tested in young men in Greenland, nor have the population-level risk factors (unemployment, social deprivation, media influences) identified in high-income countries [1]. Other explanations for marked rises among young men at the start of this period include improved reporting during the 1970s, misclassification bias, and the effects of rapid social change.

### *4.2. Findings in the Context of Other Studies*

Whilst studies we identified covered the period 1970–2011, insights into suicide patterns in Greenland during earlier periods are provided by studies meeting our exclusion criteria. The Danish physician, Dr. Alfred Bertelsen, recorded 14 suicide cases from 1891–1930 [11]. His findings, published in Danish but reported elsewhere [12], were that eight cases were men, six were women, half the men were under 35 years of age, while all the women were over 35. In cases where he was able to conduct psychological autopsies he ascertained that all had been diagnosed with mental disorders [11]. His estimates of average annual suicide rates were 4 per 100,000 for the period 1891–1903 and 3 per 100,000 for the period 1901–1930, noting that the high comparative rate for accidental deaths suggested misclassification of suicides [12]. A 1955 anthropological study concluded that, at that time, suicide deaths largely occurred in elderly people who were no longer economically active, did not wish to burden their families, and attempted suicide only after consultation with family members [30]. Our findings for the period following this, coinciding with a period of rapid sociocultural and socioeconomic change, sugges<sup>t</sup> a marked shift in risk towards much younger age groups.

Studies specifically describing suicide epidemiology in young men are lacking worldwide, and wide variation in the format of mortality statistics creates problems in comparing temporal patterns by age and gender group [1]. However, there is evidence that indigenous group status

predicts high suicide rates in young men in regions neighbouring Greenland; specifically indigenous Sami in Arctic Norway [31], Native American men aged 15–24 in the US [32], and Inuit men aged 15–24 in Canada [33]. A study of men aged 15–34 years in small Alaskan communities from 1980–2007 found that community-level characteristics such as remoteness, fewer non-Natives, and cultural divides had higher suicide risks, whilst those with higher incomes, more married couples, and traditional elders had lower risks [34]. This is consistent with evidence that rural or remote residence is associated with risk of suicide in young men in Denmark, with explanations relating to the migration of healthy workers to cities, and the increasing socioeconomic disparity between men in rural and urban areas [35]. Analysis of data from Danish longitudinal psychiatric registers shows that Greenlandic men aged 15–24 have significantly higher first psychiatric admission rates than Danish men of the same age [36]. Psychiatric disorder is therefore implicated as one explanation for high suicide rates in young men in Greenland compared with their Danish counterparts.
