Donald Trump has built his presidential campaign on demonizing immigrant and religious minorities without regard for the damage he instills. At Tuesday night's Republican presidential debate it was more of the same. In the wake of Trump's anti-Muslim rhetoric, there have been a record number of threats, harassment and vandalism to mosques, as well as attacks on individuals perceived to be Muslim. Muslim-Americans report feeling fearful, and anxious for themselves and their families. It is a difficult time for law-abiding Muslims in America.

Two decades of public health scholarship confirms that this type of hatred directed at one group of people, along with the harassment, discrimination and segregation that follow, has a pernicious impact on health. Hatred stigmatizes and marginalizes its targets, limits access to life's opportunities and reduces the freedom to freely partake in life's enjoyments. It can incite threats and violence and internalized self-hatred. The constant stress of being targeted risks cardiovascular disease, hypertension, anxiety and depression.  As the nation aspires to achieve health equity, the impact of Trump's disparaging divisive rhetoric will exacerbate troublesome health disparities.

Beginning on the day he launched his campaign with a speech vilifying Mexican Americans as drug traffickers, criminals and rapists, Donald Trump's presidential run has championed intolerance and demagoguery.  He now has the Muslim community in his cross-hairs. making false and discredited claims that a group of thousands of people with a "heavy Arab population" cheered as the Twin Towers collapsed He has suggested a Muslim American registry, the closure and monitoring of mosques and a plan to ban Muslims from entering the U.S.

Authorities report bomb threats and death threats made to mosques, the beating of a Muslim store owner by a customer who reportedly said "I'll kill Muslims", vandalism, fire at a Somali restaurant, and a severed pig's head left outside a mosque.  "A pigs head at a mosque in Philadelphia, a girl harassed at a school in New York, hate mail sent to a New Jersey mosque … I can't event count the amount of hate mail and threats we have received," said Ibrahim Hooper, a spokesman for the nation's largest Muslim civil rights group  Council for American-Islamic Relations (CAIR). A few days ago the CAIR D.C. headquarters of was evacuated after staff opened a hate-filled letter containing a suspicious substance.

Public health scholars have developed a large body of research showing this type of hate-based activity has a damaging and pervasive effect on the physical and mental health of populations. Experiences of racial discrimination and racism have frequently been associated with negative psychological outcomes, such as anxiety, depression and psychological distress.  Increased hypertension in African Americans has been linked to racial discrimination.  Racial segregation has been associated with poor pregnancy outcomes in African American women.

Harassment and discrimination based on sexual orientation show similar negative health outcomes. A study of lesbian, gay, bisexual, transgendered (LGBT) high school students living in Boston neighborhoods with high incidents of LGBT assault found the teens were significantly more likely to report suicidal ideation or attempts.  Another study found that sexual minorities living in high prejudice areas had an increased risk of mortality compared to people living in more accepting communities.

A few researchers have explored the impact of Islamophobia on the mental and physical health of Muslims. The Runnymede Trust, an independent race equality think tank in the United Kingdom, issued the influential report in 1997, Islamophobia – a Challenge for Us All, to understand the impact and extent of Anti-Muslim prejudice in England.  They noted a significant social exclusion and exposure to physical violence and harassment with the consequence that Muslims were not able to play a full part in society.

Two more recent studies evaluating the impact of anti-Muslim discrimination focused on health changes since 9/11.  A study of members of the British Muslim community before and after 9/11 showed exposure to the increase in anti-Muslim discrimination worsened blood pressure, cholesterol, BMI and self-assessed general health.  A similar study of Arab Americans in Detroit found post 9/11 abuses and discrimination were associated with increased psychological distress, reduced levels of happiness, and worse health status.

To be sure, Trump is not the only presidential candidate or politician engaged in anti-Muslim hate rhetoric.   Jeb Bush has said he would allow Christian refugees from Syria in the country—but not Muslims. Ben Carson has said he would not support a Muslim for president because faith might not be "consistent" with the U.S. Constitution. Ted Cruz has attended numerous events sponsored by anti-Muslim hate groups. But Trump's extremism and its widespread media coverage has led other candidates to worsen their campaign rhetoric and immigration proposals to keep up.

It may be, as the on line news source Vox suggests, Trump's rhetoric is a politically motivated ploy to keep himself in the middle of a media firestorm and feed the fear of his followers. It may be his way to distinguish himself from his fellow candidates as a "straight talker." No matter. He spews hatred which begets more hatred and causes real health related harm to the communities he slanders.

Nan Feyler, JD, MPH, is the Phyllis W. Beck Professor of Law at Temple University Beasley School of Law.

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