Study: Depression in Middle Age Linked to Dementia Later On

Middle-aged men and women suffering from depression may be more susceptible to dementia down the line, a recent study reports in the Archives of General Psychiatry.

Previous studies have linked depression in older adults with dementia and Alzheimer’s disease, but it has never been clear which came first: was depression a risk factor for dementia or an early symptom? The new study sought to look at depression at younger ages to see if the condition preceded memory decline.

“We wanted to look at whether depression is truly causal, or if it’s a reaction to cognitive impairment, or if the changes in the brain are causing both depression and cognitive decline at the same time,” says study author Dr. Deborah Barnes of the University of California, San Francisco, and the San Francisco Veterans Affairs Medical Center.

(MORE: Study: Eating Omega-3s May Help Reduce Alzheimer’s Risk)

To clarify the timing of depression and memory loss onset, the research team conducted a life-course study that first looked at the incidence of depression in midlife. The team included more than 13,000 people ages 40 to 55 who were part of the Kaiser Permanente Medical Care Program of Northern California and participated in a health examination called the Multiphasic Health Checkup between 1964 and 1973.

As part of the examination, the participants answered detailed questions about their health behaviors and medical histories, and had their height, weight and blood pressure recorded. Researchers were able to determine whether people had suffered from depression based on the self-reported information. The researchers then looked at the same people again between 1994 and 2000 to see if they were depressed in older age. Some years later, between 2003 to 2009, when the average age of the participants was 81, the researchers followed up to see whether they were diagnosed with dementia or Alzheimer’s disease.

The study found that 14.1% of study participants had midlife depression only, 9.2% had depression only in late life, and 4.2% were depressed during both life stages. During the final six years of follow-up, 22.5% of patients were diagnosed with dementia, 5.5% were diagnosed with Alzheimer’s disease and 2.3% were diagnosed with vascular dementia — a type of dementia resulting from brain damage due to impaired blood flow to the brain. (By contrast, Alzheimer’s disease is caused by protein deposits that interfere with brain function.)

(MORE: New Research on Understanding Alzheimer’s)

Overall, compared with people who had never been depressed, those who had depressive symptoms in middle age (but not later in life) were about 20% more likely to develop dementia later on. People who became depressed in later life were even worse off: they were 70% more likely to develop dementia than their non-depressed peers.

Further, people with late-life depression were twice as likely to have Alzheimer’s disease as those who were depression-free, and those with both midlife and late-life depressive symptoms had more than a three-fold increase in vascular dementia risk.

Because of its observational nature, the study could not firmly establish a causal association, but the findings do suggest that depression precedes vascular dementia. “The people who had depression in their mid- and late-life had an increased risk of developing vascular dementia, and [the depression] could be a true causal risk factor,” says Barnes.

She notes that it’s possible that vascular changes in the brain attributable to depression — particularly in those who have chronic depression — may increase later dementia risk. “These ongoing vascular problems are probably why they had increased risk of vascular depression,” she says.

(MORE: To Ward Off Dementia, Try Staying Healthy from Head to Toe)

As far as the link with Alzheimer’s disease is concerned, however, Barnes says depression may more likely be an early symptom, a part of the overall neurodegenerative process that leads to memory loss. “Some of the neurons in the brain that are being influenced could deal with memory and cognitive functions, but some might also be related to mood changes,” says Barnes.

The authors say that further research is needed to confirm their findings, and they acknowledge that the current study had some weaknesses: for one thing, midlife depression was assessed using a single question on a questionnaire. The dementia diagnoses were also based only on reported symptoms and medical histories and did not involve brain imaging or tests of spinal fluid. The researchers also did not look at depression history prior to midlife nor did they take into account the influence of genetic factors on Alzheimer’s disease.

The authors are hopeful that continued research will explore all of these unanswered questions and, most importantly, determine whether treating depression in midlife can help stave off later dementia. It’s a difficult area of research since it is unethical not to treat someone with reported depression and thus hard to find comparisons.

“One of our take home messages is that depression in older adults is not something that should be ignored,” says Barnes. “Depression is not a normal part of aging. … Depression can be devastating by itself, but it can also be associated with increased risk of developing dementia and it is likely to a precursor to dementia. Older adults should be followed a little closer to see if they develop these impairments and depression.”

Read more: http://healthland.time.com/2012/05/08/study-depression-in-middle-age-linked-to-dementia-later-on/#ixzz1uRjDGp8v

How I’m fighting depression with exercise

2012-04-23

Depression is a challenging, albeit important, discussion. It is even difficult to write about.

I am one of many who occasionally suffer from depression. It is usually just a minor case of the blues, but on occasion it turns into all out sadness – so much so you ache.

You purposely stay away from things that make you happy, you don’t like yourself, and you cry a lot (when you’re alone). You hate yourself for feeling badly while really being so incredibly fortunate.

My guess is that this fact would be a shock to the great majority of people who know me or work with me because I hide it so well. On the outside, I am always thought of as the happy one, the positive one, the person who is always smiling. If I were in a beauty pageant I would be in the running for Miss Congeniality!

On the inside, my life is filled with pain and emotions that are either incredibly high or incredibly low. It’s exhausting.

Continue reading How I’m fighting depression with exercise →

Why Shift Work and Sleeplessness Lead to Weight Gain and Diabetes

Studies show that shift work and other sleep disturbances like jet lag can disrupt your body clock and increase the risks of obesity and diabetes. But, until now, researchers haven’t really been sure exactly how these changes affect the body’s metabolism.

To find out, Dr. Orfeu Buxton, an assistant professor in the division of sleep medicine at Harvard Medical School, and his colleagues invited 21 men and women to participate in a study in a controlled laboratory setting, where they would have their sleep-wake cycles purposefully disrupted. Over the course of five weeks, the researchers determined when and how much the participants slept, ate and exercised. Although lab-based studies have previously examined the health effects of interferences with the body’s natural circadian rhythm, most of those trials have lasted only about a week or two.

Buxton, who is also an associate neuroscientist at Brigham and Women’s Hospital, was interested in analyzing the effects on metabolism and diabetes risk of longer-term, or chronic, changes to the circadian clock — such as those experienced by shift workers and frequent travelers.

After an initial period of adequate sleep, in which the men and women spent 10 hours in bed each night, Buxton and his team gradually started to dial back the amount of the participants’ slumber. In addition to getting less sleep, the study volunteers were also asked to go to bed and wake up four hours later each day while in the lab, a technique devised to mimic traveling one east-west time zone per day. Eventually, the participants found themselves sleeping during the day and waking at night, just as shift workers do. “We imposed a disrupted cycle and schedule of activities, from sleeping, waking, eating and fasting that was in misalignment with their endogenous 24-hour circadian clock,” says Buxton. “Nobody would do a night shift as punishing as this.”

What Buxton and his colleagues found, however, was worth the trouble. The resting metabolic rate of the volunteers by the end of the five weeks was 8% lower than where they had started. Over a year, says Buxton, such a slowdown of metabolism could translate into a 10-lb. weight gain if people’s diet and exercise habits remained the same. That could explain why night shift workers tend to gain more weight and have a higher likelihood of obesity than day workers; such weight gain is linked to an increased risk of diabetes and heart disease.

The scientists learned something else interesting about another mechanism that put the disrupted sleepers at higher risk of diabetes: the combination of having their circadian clocks reversed (sleeping during the day and waking at night) and the poorer sleep they got as a result had an effect on their insulin levels. After three weeks in the lab, the participants produced about a third less insulin from the pancreas in response to meals; with less insulin available to break down glucose, blood glucose levels started to rise and three of the 21 volunteers showed high enough levels to qualify them as pre-diabetic. (Fortunately, during the nine day washout period at the end of the study, during which participants were allowed to resume their natural day-night cycles, their glucose levels went back down to normal.)

The findings suggest that circadian disruptions combined with inadequate sleep affect the body differently than does sleep deprivation alone. In previous studies in which volunteers slept less, but maintained their natural sleep-wake cycles, they showed less sensitivity to insulin, but there was no change in the amount of insulin released by the pancreas. In the current study, adding changes to the circadian clock seemed to have a more profound effect on the pancreas. Both pathways can contribute to an increased risk of diabetes, but in different ways, says Buxton. “The body responds to sleep restriction in one way, and circadian disruption combined with sleep restriction in a very different way,” he says.

The findings highlight how important the sleep-wake cycle can be for metabolism and health. “It’s harder to dismiss the [observational] studies and workplace studies that show night work is a health risk,” he says. “We’ve shown unhealthy mechanisms can occur even in healthy subjects, so the time for dismissing night work as a health risk is well past.”

The same is true for jet lag, especially if it’s persistent, such as for pilots and other flight personnel. Buxton is hoping to study pilots in training before they start regularly crossing time zones, to see if the same effects he found in the lab also appear in the real world. In the meantime, it’s worth noting that while much of the attention for preventive health has focused on diet and exercise, sleep is an important part of that equation. “If you’re not getting enough sleep, then it’s hard to find the energy to exercise,” says Buxton. “And if you’re not getting enough sleep, you not only eat more than you need but you tend to make poorer food choices. So in terms of obtaining optimum health, all three pillars — diet, exercise and sleep — are important.”

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.

Read more: http://healthland.time.com/2012/04/12/why-shift-work-and-sleeplessness-lead-to-weight-gain-and-diabetes/?iid=hl-main-lede#ixzz1rtW8Uj77