America is facing a suicide epidemic. In 2017, the most recent year for which the Centers for Disease Control shared data, 14 out of 100,000 people died of suicide, compared to 10.5 in 1999, an increase of 33%. Among rich countries, only Japan and Finland have higher suicide rates.

A study published earlier this month by the Journal of Epidemiology & Community Health looks at the link between minimum wage and suicide, investigating the relation between public policy and mental health. Researchers examined data on suicides that occurred in all states between January 1990 and December 2015, and analyzed how the incidence of suicide changed with a higher minimum wage.

They found it did change: A relatively small increase in the minimum wage significantly reduced the occurrence of suicide amongst low-income people.

The study used education level as a proxy for likelihood of working minimum wage jobs. Adults between aged 16 to 64 were divided in two groups: people with a high school diploma or lower level of education, and people whose education was higher than high school.

The first was the study group, on which the effects of minimum wage changes were expected to have a higher impact, while the second acted as a control group. The study looked at the average across states, so as not to have to control for factors that could impact the suicide rates, such as other progressive policies, or levels of rural versus urban living. The results point to what the effect of a higher minimum wage would be at the federal level.

The findings are striking: A $1 increase in minimum wage was linked to a reduction of suicide ranging between 3.4% and 5.9% amongst adults with high school diplomas or less. The impact was measured right as the minimum wage was raised, and then after a one-year lag. The effects were more striking one year from the increase, suggesting that people had the time to experience the positive effects of the wage increase.

John Kaufman, a PhD student in epidemiology at Emory University and one of the study’s authors, told Quartz that the increase in minimum wage wasn’t studied in isolation. The researchers also looked at the role of such an increase in concomitance with unemployment.

What they found is that where unemployment is higher, the effect of a minimum wage increase tends to be stronger. One hypothesis as to why, says Kaufman, is that “during an economic recession people are more likely to have to work on minimum wage jobs.”

Though the study only focuses on the impact of salary increase, it also suggests the impact that social policy can have on public health. “It’s important for people to realize that there are societal factors that impact mental health,” said Kaufman, “even if the conversation is often focused on the individual level.”

The link between poverty and suicide has been investigated before. But the extent to which even a small increase of minimum wage could impact public health is especially striking when compared to the increases seen in executive salaries, and particularly CEO’s. In 1990, the federal minimum wage was $3.80 per hour. In 2015, it was $7.25. While low-level salaries have not risen much, high-level ones have: CEO salaries rose 438% in the same span of time. In 1990, the CEO-to-worker salary ratio was about 54. In 2015, it was 215.

Minimum wages aren’t the only way in which income distribution impacts well-being, suggesting inequality can be seen as a public health issue. For instance, the life expectancy of the top 20% in the US has gone up in the past decade, while it’s gone down for the bottom 20%, and the levels of cardiovascular disease are higher the greater the levels of inequality. Conversely, countries with lower levels of inequality tend of enjoy longer life expectancy and lower infant and childhood mortality.