Welcome to Los Angeles, CA

In adults of all ages, chronic sleep problems were linked with a greater risk of trouble with activities of daily living later in life, in a recent study.

Although disability rates have been falling, up to one in five seniors have at least one limitation in their ability to perform tasks, the researchers write in the Journal of the American Geriatrics Society.

"Most people don't get sufficient sleep - as a culture we tend to devalue sleep - and we tend to underestimate the potential impact of not getting adequate sleep," lead author Elliot Friedman told Reuters Health by email.

Research has linked poor sleep to poor health, but little is known about how sleep affects daily functioning, said Friedman, a gerontologist at Purdue University in West Lafayette, Indiana.

For the new study, Friedman analyzed survey data collected in 1995-1996 and then again in 2004-2006 from 3,620 people between the ages of 24 and 75 at the outset.

Participants answered questions about any sleep issues they had in the past year and their ability to complete daily living tasks such as bathing, dressing, and walking one block. They also reported on their ability to complete more difficult 'instrumental' tasks such as bending over, vacuuming, carrying groceries, climbing stairs, walking a mile, or running.

At both surveys, about 11 percent of participants reported chronic sleep issues.

Read more on FOX NEWS.

A selection of issues at stake in the presidential election and their impact on Americans, in brief:

EXECUTIVE AUTHORITY

"Your Majesty" isn't in the American political lexicon. But when a president sets a major policy by edict, skirting Congress, it sets off a debate that traces back to the time of kings and queens -- and the Founding Fathers who rejected the authority of the crown. Lawmakers cry foul when a president, especially of the other party, usurps their authority through executive action. Defenders say it can be the only way to get something done when Congress is gridlocked.

President Barack Obama has used executive authority expansively, most notably on immigration.

Donald Trump says he'd make sure Obama's "unconstitutional actions" never come back. But some Republicans worry that Trump, too, might pursue an "imperial presidency." Hillary Clinton supported Obama's unilateral move to curb deportation of millions of immigrants in the U.S. country illegally. The Supreme Court deadlocked in June over the major portion of the immigration executive actions, effectively killing the plan for the rest of Obama's presidency.

___

MINIMUM WAGE

Modest income gains, strikes by fast-food workers, the rapid growth of low-paying jobs while middle-income work shrinks. These factors have combined to make the minimum wage a top economic issue for the 2016 campaign.

Millions would benefit from higher pay, of course. But an increase in the minimum wage would also boost costs for employers and may slow hiring.

Hillary Clinton supports raising the minimum wage at least to $12 an hour, even higher at state and local levels. Donald Trump has said he supports an increase to $10, but thinks states should "really call the shots." The federal minimum wage now is s $7.25.

Why the momentum for higher minimums? The typical household's income has fallen 2.4 percent since 1999. Low-paying industries, such as retail, fast food and home health care aides, are among the largest and fastest-growing. And many low-wage workers are older, have families and are probably more willing to demand higher pay.

___

WALL STREET REGULATION

The debate over rules governing banks and the markets comes down to this: how to prevent another economic catastrophe like the Great Recession ignited by the financial crisis in 2008. The worst upheaval since the 1930s Depression wiped out $11 trillion in U.S. household wealth and about 8 million jobs. More than 5 million families lost their homes to foreclosure.

The economic recovery over eight years has been halting and slow.

The goal behind the most radical overhaul of financial rules since the 1930s was to rein in high-risk practices on Wall Street and prevent another multibillion-dollar taxpayer bailout of banks. In the package of rules Congress enacted in 2010, regulators gained new tools to shut banks without resorting to bailouts. Risky lending was restricted and a new federal agency was charged with protecting consumers from deceptive marketing of financial products.

Republicans and many in the business community say the restrictions have raised costs for banks, especially smaller ones. They want the overhaul law repealed. Donald Trump calls it a "disaster," saying he would dismantle most of it.

Hillary Clinton says the financial rules should be preserved and strengthened.

___

INFRASTRUCTURE

The nation's infrastructure is in need of repair and improvement. On that, politicians generally agree. Harder to answer: How to pay for it and which projects take priority.

A reliable infrastructure system is important for the nation's economy, safety and quality of life.

Public health can be put at risk by poor infrastructure, such as the lead-tainted pipes that contaminated the water supply of Flint, Michigan.

Poorly maintained highways and congested traffic also can raise the cost of shipping goods and the price consumers pay.

A recent report by the American Society of Civil Engineers projects the U.S. will face a $1.4 trillion funding gap for its infrastructure by 2025.

Democrat Hillary Clinton wants to spend $250 billion over the next five years on public infrastructure and direct an additional $25 billion to a new infrastructure bank to help finance local projects. Republican Donald Trump has said he wants to spend at least double that amount on infrastructure, financed with bonds. Whoever becomes president, it's a staggering amount of money for the federal treasury to put out -- if Congress goes along.

___

IRAN

Last year's nuclear deal with Tehran has removed for now the threat of a U.S.-Iranian military confrontation. But the deal rests on shaky ground.

The accord curtailed Iran's nuclear program, pulling it back from atomic weapons capability in exchange for the end of many economic sanctions.

But the next U.S. president could have his or her hands full, dealing with Iran in general and the agreement in particular. Various restrictions on Iran start ending in about seven years.

For Hillary Clinton and Donald Trump, it's basically a question of continuity versus change.

As secretary of state, Clinton helped lay the groundwork for the pact. She supports it, while taking a generally tougher tone on Iran than President Barack Obama.

Trump hates the deal. But he contends that he can renegotiate its terms.

Both are prepared to use force to prevent Tehran from acquiring the bomb. If the deal collapses or expires without sufficient safeguards, that possibility is back in play.

___

REFUGEES

With millions of Syrians displaced by a years-long war and hundreds of thousands of people fleeing to Europe, countries around the world are being pressed to help resettle people seeking refuge.

The United States pledged to accept 10,000 such refugees by the end of the budget year in September and did so, a month early.

Republicans have balked at the idea of allowing people from Syria into the United States and Donald Trump has called for a halt on refugee resettlement for them. He says vetting of these refugees is inadequate.

Hillary Clinton has pledged to expand the Syrian refugee program and allow as many as 65,000 such refugees into the United States.

The fate of the program almost certainly hinges on the outcome of the November election.

___

CHILD CARE/PAY EQUITY

In much of the U.S., families spend more on child care for two kids than on housing. And if you're a woman, it's likely you earn less than your male colleagues. That's according to the latest research, which suggests that while the U.S. economy has improved, women and their families are still struggling to make the numbers work.

Clinton wants a 12-week government-paid family and medical leave program, guaranteeing workers two-thirds of their wages up to a certain amount. Trump proposes six weeks of leave for new mothers, with the government paying wages equivalent to unemployment benefits. Both candidates propose tax relief for child care costs. Trump's plan provides for a new income tax deduction for child care expenses, other tax benefits and a new rebate or tax credit for low-income families. Clinton says no family should spend more than 10 percent of its income on child care and has called for child-care subsidies and tax relief offered on a sliding scale.

Clinton also favors forcing businesses to disclose gender pay data to the government for analysis. Trump says only that working moms should be "fairly compensated."

Women comprise about 57 percent of the labor force and many of them have young children. If they aren't getting paid enough to make ends meet, more families will seek out government aid programs or low-quality, unlicensed daycares for their children.

___

EDUCATION

Education is a core issue not just for students and families, but for communities, the economy, and the nation as a global competitor.

The country has some 50 million K-12 students. Teaching them, preparing them for college and careers, costs taxpayers more than $580 billion a year, or about $11,670 per pupil per year. A better education usually translates into higher earnings.

And while high school graduations are up sharply and dropout rates down, the nation has a ways to go to match the educational outcomes elsewhere. American schoolchildren trail their counterparts in Japan, Korea, Germany, France and more.

For students seeking higher education, they face rising college costs and many are saddled with debt.

Hillary Clinton has proposed free tuition at in-state public colleges and universities for working families with incomes up to $125,000 -- free for families, that is, not for taxpayers. Donald Trump has focused on school choice, recently proposing to spend $20 billion in his first year in office to expand programs that let low-income families send their children to the local public, private, charter or magnet school that they think is best.

___

STUDENT DEBT

More Americans are getting buried by student debt -- causing delays in home ownership, limiting how much people can save and leaving taxpayers at risk as many loans go unpaid.

Student debt now totals around $1.26 trillion. This amounts to a stunning 350 percent increase since 2005, according to the New York Federal Reserve.

More than 60 percent of the class of 2014 graduated with debt that averaged nearly $27,000, according to the College Board. Not all that taxpayer-backed debt is getting repaid. Out of the 43 million Americans with student debt, roughly 16 percent are in long-term default -- a potential hit in excess of $100 billion that taxpayers would absorb.

Democrat Hillary Clinton proposes no tuition for students from families making less than $85,000 who go to an in-state, public college. Republican Donald Trump has promised a "great" student debt plan, details to come.

___

IMMIGRATION

The future of millions of people living in the U.S. illegally could well be shaped by the presidential election. The stakes are high, too, for those who employ them, help them fit into neighborhoods, or want them gone.

Republican Donald Trump at first pledged to deport the estimated 11 million immigrants in the country illegally. Not only that, he'd build a wall all along the Mexican border. But his position has evolved. He's sticking to his vow to build the wall and make Mexico pay. But he's no longer proposing to deport people who have not committed crimes beyond their immigration offences. Still, he's not proposing a way for people living in the country illegally to gain legal status.

Democrat Hillary Clinton, in contrast, would overhaul immigration laws to include a path to citizenship, not just legal status.

Illegal immigration has been at nearly 40-year lows for several years. It even appears that Mexican migration trends have reversed, with more Mexicans leaving the U.S. than arriving. Billions of dollars have been spent in recent years to build fencing, improve border technology and expand the Border Patrol.

Nonetheless the Mexican border remains a focal point for those who argue that the country is not secure.

___

CLIMATE CHANGE

It's as if Donald Trump and Hillary Clinton live on two entirely different Earths: one warming, one not. Clinton says climate change threatens us all, while Trump repeatedly tweets that global warming is a hoax.

Measurements and scientists say Clinton's Earth is much closer to the warming reality. And it is worsening.

The world is on pace for the hottest year on record, breaking marks set in 2015, 2014, and 2010. It is about 1.8 degrees warmer than a century ago.

But it's more than temperatures. Scientists have connected man-made climate change to deadly heat waves, droughts and flood-inducing downpours.

Studies say climate change is raising sea levels, melting ice and killing coral. It's making people sicker with asthma and allergies and may eventually shrink our bank accounts.

The American Association for the Advancement of Sciences says warming can be highly damaging to people and the planet and potentially irreversible.

___

ROLE OF GOVERNMENT

It's the Goldilocks conundrum of American politics: Is the government too big, too small or just right? Every four years, the presidential election offers a referendum on whether Washington should do more or less.

Donald Trump favors cutting regulation and has promised massive tax cuts, but his plans are expected to add trillions to the national debt. Unlike most conservatives, he supports eminent domain and has spoken positively about government-run health care. And don't forget that massive border wall. Hillary Clinton has vowed new spending on education and infrastructure that could grow government, too. She strongly supports "Obamacare," which most small government proponents see as overreach.

At its heart, the debate about government's reach pits the desire to know your basic needs will be cared for against the desire to be left alone. For the last few decades, polls have found Americans generally feel frustrated by the federal government and think it's wasteful. A smaller government sounds good to a lot of people until they're asked what specific services or benefits they are willing to do without.

___

DEBT

The federal government is borrowing about one out of seven dollars it spends and steadily piling up debt. Over the long term, that threatens the economy and people's pocketbooks.

Most economists say rising debt risks crowding out investment and forcing interest rates up, among other problems. At the same time, rapidly growing spending on federal health care programs like Medicare and the drain on Social Security balances caused by the rising tide of baby boomers could squeeze out other spending, on roads, education, the armed forces and more.

It takes spending cuts, tax increases or both to dent the deficit. Lawmakers instead prefer higher spending and tax cuts.

Neither Hillary Clinton nor Donald Trump has focused on the debt.

Trump has promised massive tax cuts that would drive up the debt and he's shown little interest in curbing expensive benefit programs like Medicare.

Clinton, by contrast, is proposing tax increases on the wealthy. But she wouldn't use the money to bring down the debt. Instead, she'd turn around and spend it on college tuition subsidies, infrastructure and health care.

___

TRADE

In this angry election year, many American voters are skeptical about free trade -- or hostile to it.

The backlash threatens a pillar of U.S. policy: The United States has long sought global trade.

Economists say imports cut prices for consumers and make the U.S. more efficient.

But unease has simmered, especially as American workers faced competition from low-wage Chinese labor. Last year, the U.S. ran a $334 billion trade deficit with China -- $500 billion with the entire world.

The Democratic and Republican presidential candidates are both playing to public suspicions about trade deals. Hillary Clinton broke with President Barrack Obama by opposing an Asia-Pacific trade agreement that she had supported as secretary of state.

Donald Trump vows to tear up existing trade deals and to slap huge tariffs on Chinese imports.

But trade deals have far less impact on jobs than forces such as automation and wage differences between countries. Trump's plans to impose tariffs could start a trade war and raise prices.

___

SUPREME COURT

The ideological direction of the Supreme Court is going to tip one way or the other after the election. The outcome could sway decisions on issues that profoundly affect everyday Americans: immigration, gun control, climate change and more.

The court has been operating with eight justices since Antonin Scalia died in February. His successor appears unlikely to be confirmed until after the election, at the earliest. The court is split between four Democratic-appointed, liberal justices and four conservatives who were appointed by Republicans -- although Justice Anthony Kennedy has sided with the liberals on abortion, same-sex marriage and affirmative action in the past two years.

The ninth justice will push the court left or right, depending on whether Democrat Hillary Clinton or Republican Donald Trump becomes president. President Barack Obama has nominated Merrick Garland to take Scalia's seat, but the Republican Senate has refused to consider Garland's nomination, in an effort to prevent a liberal court majority.

___

CHINA

Tensions have been rising over China's assertive behavior in the seas of Asia. The U.S. also accuses China of unfair trading practices and cyber theft of business secrets.

Donald Trump says that the sheer volume of trade gives the U.S. leverage over China. He accuses China of undervaluing its currency to make its exports artificially cheap and proposes tariffs as high as 45 percent on Chinese imports if Beijing doesn't change its behavior. Such action could risk a trade war that would make many products in the U.S. more expensive.

Clinton says the U.S. needs to press the rising Asian power to play by international rules, whether on trade or territorial disputes.

While many of China's neighbors are unnerved by its military build-up, the wider world needs the U.S. and China to get along, to tackle global problems. The U.S. and China are also economically inter-dependent, and punishment by one party could end up hurting the other.

___

INCOME INEQUALITY

Income inequality has surged near levels last seen before the Great Depression. The average income for the top 1 percent of households climbed 7.7 percent last year to $1.36 million, according to tax data. That privileged sliver of the population saw pay climb at almost twice the rate of income growth for the other 99 percent, whose pay averaged a humble $48,768.

Dogged on the issue during the primaries by Bernie Sanders, Hillary Clinton has highlighted inequality in multiple speeches. She hopes to redirect more money to the middle class and impoverished. Clinton would raise taxes on the wealthy, increase the federal minimum wage, boost infrastructure spending, provide universal pre-K and offer the prospect of tuition-free college.

Donald Trump offers a blunter message about a system "rigged" against average Americans. To bring back jobs, Trump has promised new trade deals with better terms, greater infrastructure spending than Clinton foresees and tax cuts that he says would propel stronger growth (though independent analysts say his budget plans would raise deficits).

___

OPIOID EPIDEMIC

More than 28,000 Americans died from overdosing on opioids in 2014, a record high for the nation.

That's 78 people per day, a number that doesn't include the millions of family members, first responders and even taxpayers who feel the ripple of drug addiction in their daily lives.

A rise in prescription painkillers is partially to blame: The sale of these drugs has quadrupled since 1999, and so has the number of Americans dying from an addiction to them. When prescriptions run out, people find themselves turning to the cheaper alternative heroin and, increasingly, the even more deadly drug fentanyl.

Recovering addicts and their family members are increasingly speaking out, putting a face on drug addiction and lessening the stigma surrounding it. But dollars for prevention, treatment and recovery services are still hard to come by, leaving many people waiting weeks or months to find the treatment they're seeking. Meantime, family members empty bank accounts in search of help, while law enforcement officers and emergency rooms serve as a first line of defense.

Donald Trump says the wall he wants to build along the southern border is essential to stopping the flow of illegal drugs into the country. Hillary Clinton, meanwhile, pledges to spend $10 billion to increase access to prevention, treatment and recovery services, among other things.

___

NORTH KOREA

Pariah state North Korea could soon be capable of targeting America with nuclear weapons. What can the U.S. do to stop it?

Diplomacy and economic sanctions have not worked so far. North Korea's isolation is deepening, but it has continued to conduct nuclear test explosions and make advances in its missile technology.

Republican presidential candidate Donald Trump says the U.S. can put more pressure on China to rein in its North Korean ally. He says he is willing to meet the North Korean leader, Kim Jong Un.

Democrat Hillary Clinton wants the world to intensify sanctions as the Obama administration did with Iran, a course that eventually opened the way for a deal to contain its nuclear program.

But it will be tough to force North Korea back to negotiations that aim at its disarmament in exchange for aid. Kim views atomic weapons as a security guarantee for his oppressive regime

___

HEALTH CARE

About 9 in 10 Americans now have health insurance, more than at any time in history. But progress is incomplete, and the future far from certain. Rising costs could bedevil the next occupant of the White House.

Millions of people previously shut out have been covered by President Barack Obama's health care law. No one can be denied coverage anymore because of a pre-existing condition. But "Obamacare" remains divisive, and premiums for next year are rising sharply in many communities.

Whether Americans would be better off trading for a GOP plan is another question. A recent study found that Donald Trump's proposal would make 18 million people uninsured. GOP congressional leaders have a more comprehensive approach, but key details are still missing.

Overall health care spending is trending higher again, and prices for prescription drugs -- new and old -- are a major worry.

Medicare's insolvency date has moved up by two years -- to 2028.

Hillary Clinton would stay the course, adjusting as needed. Republicans are united on repealing Obama's law, but it's unclear how they would replace it.

___

AMERICA AND THE WORLD

How the U.S. uses its influence as the world's sole superpower is a central feature of presidential power.

It can mean taking the country to war -- to protect the homeland or to defend an ally. Or it can mean using diplomacy to prevent war. It can affect U.S. jobs, too, as choices arise either to expand trade deals or to erect barriers to protect U.S. markets.

In the contest between Hillary Clinton and Donald Trump, America's role in the world is a point of sharp differences. Each says the U.S. must be the predominant power, but they would exercise leadership differently. Trump calls his approach "America first," meaning alliances and coalitions would not pass muster unless they produced a net benefit to the U.S. Clinton sees international partnerships as essential tools for using U.S. influence and lessening the chances of war.

These divergent views could mean very different approaches to the military fight and ideological struggle against the Islamic State, the future of Afghanistan and Iraq, the contest with China for influence in Asia and the Pacific, and growing nervousness in Europe over Russian aggression.

___

VOTING RIGHTS

Voting rights in America are in flux. Republican-controlled legislatures are tightening voter laws, placing limits on early voting and same-day registration, and imposing new requirements for IDs at polling places. In 2013, the Supreme Court invalidated a key provision of the 1965 Voting Rights Act. That provision had required states with a history of racial discrimination to get federal preclearance to change election laws.

The issue has become highly partisan with the rapid growth of minority populations, which in recent presidential elections have tilted heavily Democratic.

The Obama Justice Department has challenged voter ID and other laws, saying they could restrict access for minorities and young people. Recent lower court rulings temporarily softened some of the toughest restrictions, but litigation remains knotted up with Supreme Court appeals likely. Bills in Congress to restore the Voting Rights Act are stalled.

Donald Trump opposes same-day voter registration, backing laws to ensure only citizens vote. Hillary Clinton wants Congress to restore the Voting Rights Act and seeks a national standard of at least 20 days of early in-person voting.

___

Associated Press writers Erica Werner, David A. Lieb, Bradley Klapper, Anne Flaherty, Jennifer C. Kerr, Alicia A. Caldwell, Seth Borenstein, Josh Lederman, Andrew Taylor, Kathleen Ronayne, Paul Wiseman, Mark Sherman, Josh Boak, Matthew Pennington, Ricardo Alonso-Zaldivar, Robert Burns and Hope Yen contributed to this report.

___

This story is part of AP's "Why It Matters" series, which will examine three dozen issues at stake in the presidential election between now and Election Day. You can find them at: http://apne.ws/2bBG85a

EDITOR'S NOTE _ A look at issues at stake in the election and their impact on people

WASHINGTON (AP) -- The National Museum of African American History and Culture opening this weekend in Washington took more than a decade to build. A look at some of the key milestones in its construction:

Dec. 16, 2003

President George W. Bush signs legislation creating the museum. Early on, it is scheduled to open in 2011. It is expected to cost hundreds of millions of dollars, half of which will come from Congress and the rest from donations. The idea for museum and memorial traces back to 1915 and a group of African-American Civil War veterans.

March 14, 2005

Lonnie G. Bunch III is named founding director of the museum. Before taking the job, he served as the president of the Chicago Historical Society. He had also worked at the Smithsonian's National Museum of American History from 1989 to 2000 and at the California Afro-American Museum in Los Angeles from 1983 to 1989. His appointment is effective July 2005.

Jan. 31, 2006

The Smithsonian's Board of Regents selects the museum's site on the National Mall near the Washington Monument. A total of four spots had been considered: two on the mall and two off the mall. The other site on the Mall was the Smithsonian's Arts and Industries Building. President Bush had endorsed a site on the Mall.

March 27, 2009

Officials unveil six design concepts proposed for the future museum. One concept includes a design with wetlands extending inside the museum. Another proposed design is oval-shaped.

April 14, 2009

The Smithsonian selects a winning architectural concept for the museum. The design is inspired by an African headdress, and a bronze screen that wraps the building taking inspiration from metalwork in the South. The lead designer is David Adjaye, who was born in Dar es Salaam, Tanzania, and whose parents are from Ghana.

March 10, 2010

The museum announces it will receive about 40 objects connected to abolitionist and Underground Railroad conductor Harriet Tubman, including Tubman's favorite hymnal and a shawl given to her by Queen Victoria. The donation coincides with the 97th anniversary of Tubman's death on March 10, 1913.

Feb. 22, 2012

President Barack Obama helps break ground for the museum, calling it "not just a record of tragedy, but a celebration of life." He is joined by his wife, Michelle Obama, and former first lady Laura Bush. The ceremony is hosted by actress Phylicia Rashad, who played Clair Huxtable on "The Cosby Show." Curators estimate that they have collected 15,000 to 20,000 artifacts for the museum.

May 14, 2013

The museum announces that it has acquired an object that will become a centerpiece of the collection: a slave cabin. The two-room cabin is from a former cotton plantation on Edisto Island in coastal South Carolina. It is taken apart board by board so it can be transported. "The reason we collect a cabin like this is it allows you to humanize the slavery experience," museum director Lonnie Bunch says at the time.

June 11, 2013

The museum announces a $12 million gift from Oprah Winfrey and says that the museum's 350-seat theater will be named after her. Winfrey had also given $1 million in 2007. Other major donors with recognizable names include: the Bill & Melinda Gates Foundation; TV producer and writer Shonda Rhimes of "Grey's Anatomy" and "Scandal" fame, and philanthropist David M. Rubenstein, who has donated millions to other high-profile Washington projects. The museum is projected to cost $500 million.

Nov. 17, 2013

The museum installs its first artifacts: a Jim Crow-era railroad car and prison guard tower from the Louisiana State Penitentiary. The objects are so large they have to be hoisted in by cranes as the museum is being built. The railroad car weighs 77 tons. The tower is approximately 21 feet tall and 14 feet wide.

April 14, 2015

The first of the 3,600 bronze-colored screen panels surrounding the building are installed. The panels are inspired by ironwork created by slaves in New Orleans and Charleston, South Carolina. The initial plan was for the panels to be made of bronze. After that was found to be too expensive and too heavy, designers eventually settled on aluminum finished to look like bronze.

June 3, 2015

A construction worker working on the roof of the museum dies in a construction accident. He is identified as 35-year-old Ivan Smyntyna of Roswell, Georgia.

Sept. 24, 2016

President Barack Obama will speak at the dedication of the museum, the Smithsonian's 19th.

WATCH THE OPENING CEREMONY LIVE:

Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.