Morning people may have a lower risk of breast cancer, says study

Sleep traits could be a risk factor for breast cancer, new research suggests. Women who said they preferred to get out of bed early were found to have a lowe...

Posted: Jun 27, 2019 8:56 AM

Sleep traits could be a risk factor for breast cancer, new research suggests. Women who said they preferred to get out of bed early were found to have a lower risk of breast cancer than those who stay up late.

However, experts cautioned that other breast cancer risk factors such as alcohol consumption and being overweight have a greater impact than sleep and said there was no reason to change your sleep patterns.

One out of 100 women who considered themselves morning people developed breast cancer, compared with two in 100 women who described themselves as evening people, according to the study, which was published Wednesday in the BMJ.

The study also found that sleeping more than the average seven to eight hours per night was found to have a slightly increased risk of breast cancer. It also found there was little link with insomnia.

Researchers used information from more than 400,000 women in two large data banks -- around 180,000 women from UK Biobank study and more than 220,000 women from the Breast Cancer Association Consortium study. Participants' preference for waking early or late was included in the data.

"It is important to note that these data do not suggest in any way that modifying sleep habits could eventually lead to a decrease in the risk of breast cancer," Luca Magnani, senior research fellow in the department of Surgery & Cancer at Imperial College London told the Science Media Centre.

"What they suggest is that it appears that the risk of breast cancer is associated with a genetic (thus not modifiable) trait that is in itself associated with a "morning" or "night" preference -- what we call 'larks' and 'owls'."

According to 2016 figures from the charity Cancer Research UK, breast cancer is the most common type of cancer in the UK. In the US, the American Cancer Society estimates that more than 260,000 cases of invasive breast cancer will be diagnosed in women in 2019.

Dr. Dipender Gill, a Wellcome Trust clinical research fellow at Imperial College London, said the paper is a "useful progress in the field." The study findings add to previous research suggesting a link between sleep-related behaviors and risk of negative health outcomes, he said in an email to CNN.

But the study doesn't shed light on what process causes sleep traits to affect breast cancer risk. "It may be that certain factors that affect sleep-related behaviors also affect breast cancer risk through a separate mechanism," explained Gill.

In this case, improving sleeping patterns would not necessarily reduce the risk of breast cancer, he said. "There is still some way to go before we fully understand the implications of sleeping patterns on health."

The study was first presented in November 2018 at the NCRI Cancer Conference in Glasgow.

Read: Sleep: Do you get enough?

Genes, sleep and health

Co-author Caroline Relton, professor of epigenetic epidemiology at the University of Bristol, in the UK, said that sleep had systemic and far-reaching consequences on people's health.

"The message is that perhaps people don't fully appreciate that sleep is really important and does have health benefits beyond not feeling physically tired and being cognitively alert and so forth," said Relton, who is also director of the Bristol Population Health Science Institute.

"The main lifestyle risk factors that we know are clearly associated with breast cancer are alcohol intake and obesity or high Body Mass Index," said Relton.

"Sleep is likely to be an important risk factor for breast cancer, but it isn't as large as other well-established risk factors like BMI or alcohol," said lead author Dr. Rebecca Richmond, last year. Richmond is currently a research fellow at the MRC Integrative Epidemiology Unit at the University of Bristol.

Our genes are now known to influence whether we're early risers or not and our "chronotype" -- or time of day preference -- affects not only your sleep patterns but your hormone levels and core body temperature. However, it's not entirely innate. Lifestyle factors, including diet, daily activities and exposure to artificial light, influence your chronotype.

In an editorial linked to the study, Eva Schernhammer, a professor from the University of Vienna said the findings identified "a need for future research exploring how the stresses on our biological clock can be reduced."

It's the people with the biggest mismatch between their chronotype and daily activities that are most at risk, she said.

Schernhammer cited observational studies that suggested that unlike night owls, early risers that work night shifts have an increased risk of type 2 diabetes. This provided "additional support for the biological importance of circadian misalignment," she said.

Indiana Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 52037

Reported Deaths: 2762
CountyConfirmedDeaths
Marion12111693
Lake5677249
Elkhart366260
Allen2971134
St. Joseph221169
Hamilton1735101
Cass16489
Hendricks1470100
Johnson1351118
Porter84938
Vanderburgh8016
Tippecanoe7859
Clark71944
Madison68164
LaPorte62928
Howard61058
Bartholomew60545
Kosciusko5844
Marshall57011
Noble52428
Boone49244
LaGrange48710
Delaware48152
Jackson4793
Hancock47436
Shelby46025
Floyd41844
Monroe36128
Morgan34431
Grant32226
Dubois3196
Henry30318
Montgomery29720
Clinton2903
White27810
Dearborn27123
Warrick26829
Vigo2618
Decatur25732
Lawrence25325
Harrison21822
Greene19932
Miami1942
Jennings17912
Putnam1748
DeKalb1694
Scott1659
Wayne1596
Daviess15117
Perry15110
Steuben1402
Orange13823
Jasper1362
Ripley1357
Franklin1288
Gibson1282
Wabash1193
Carroll1142
Starke1093
Fayette1087
Whitley1086
Newton10110
Huntington942
Jefferson872
Wells831
Randolph804
Fulton761
Jay720
Knox710
Washington681
Pulaski661
Clay645
Posey640
Rush623
Spencer591
Owen531
Benton510
Sullivan511
Adams491
Brown441
Blackford402
Fountain362
Crawford330
Tipton331
Switzerland320
Parke280
Martin260
Ohio230
Vermillion200
Warren151
Union140
Pike120
Unassigned0193

Ohio Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 66853

Reported Deaths: 3064
CountyConfirmedDeaths
Franklin12301449
Cuyahoga9359399
Hamilton7046208
Lucas3079306
Marion275539
Montgomery257936
Summit2382209
Pickaway222942
Mahoning1971239
Butler189747
Columbiana139560
Stark1244116
Lorain118970
Trumbull106678
Warren101826
Clark82010
Delaware76315
Fairfield71917
Lake62723
Tuscarawas62110
Licking60012
Medina59932
Belmont57324
Clermont5157
Miami51431
Wood51051
Portage50960
Ashtabula45244
Geauga43143
Richland3906
Allen38541
Wayne37655
Greene3659
Mercer30410
Erie30122
Holmes2625
Darke26126
Huron2602
Madison2259
Ottawa21724
Athens1921
Sandusky17615
Ross1503
Washington14720
Putnam14515
Coshocton1434
Crawford1405
Jefferson1272
Morrow1271
Hardin12512
Union1151
Auglaize1124
Muskingum1061
Preble961
Lawrence920
Clinton912
Monroe8917
Hancock871
Hocking839
Guernsey824
Scioto770
Shelby774
Williams772
Carroll713
Logan711
Ashland692
Fulton680
Wyandot665
Brown621
Fayette580
Highland581
Champaign571
Knox571
Defiance553
Van Wert491
Perry481
Seneca442
Henry370
Paulding340
Jackson310
Pike290
Adams282
Vinton232
Gallia211
Noble140
Harrison131
Meigs130
Morgan120
Unassigned00
Fort Wayne
Clear
82° wxIcon
Hi: 85° Lo: 63°
Feels Like: 83°
Angola
Clear
82° wxIcon
Hi: 84° Lo: 63°
Feels Like: 82°
Huntington
Clear
82° wxIcon
Hi: 84° Lo: 62°
Feels Like: 82°
Decatur
Clear
82° wxIcon
Hi: 85° Lo: 64°
Feels Like: 82°
Van Wert
Clear
82° wxIcon
Hi: 87° Lo: 64°
Feels Like: 82°
Storms Late Wednesday
WFFT Radar
WFFT Temperatures
WFFT National

Community Events