Adult development and aging: Biopsychosocial Perspectives, 4th edition (II)

The first post about the book is here. Below some stuff from chapters 4 and 5, which I liked a lot better than the first ones because they had a lot more data:

“The overall pattern of body weight in adulthood shows an upside-down U-shaped trend reflecting the fact that most people increase in their weight from the 20s until the mid-50s, after which their weight decreases. Most of the weight gain that occurs through the years of middle adulthood is due to an increase in BMI (Ding, Cicuttini, Blizzard, Scott, & Jones, 2007), which is manifested mainly as the accumulation of body fat around the waist and hips (commonly referred to as the ‘‘middle-aged spread’’). The loss of body weight in the later years of adulthood is not, however, due to a loss of this accumulated fat and so does not mean that older adults necessarily become healthier or more fit. Instead, older adults lose pounds because they suffer a reduction of FFM [fat-free mass] due to loss of muscle mass, even if they maintain high levels of activity (Manini et al., 2009).
At the other end of the spectrum, some older adults continue to gain weight to the point of developing a BMI that places them in the overweight or obese categories. Between the mid-1990s and mid-2000s, the percent of older adults classified as overweight increased from 60 to 69% and as obese from 22 to 31% (Houston, Nicklas, & Zizza, 2009). […]

You are able to move around in your environment due to the actions of the structures that support this movement, including the bones, joints, tendons, and ligaments that connect the muscles to the bones, and the muscles that control flexion and extension. In the average person, all these structures undergo age-related changes that compromise their ability to function effectively. Beginning in the 40s (or earlier in the case of injury), each component of mobility undergoes significant age-related losses. Consequently, a gradual reduction of walking speed occurs (Shumway-Cook et al., 2007). […] The adult years are characterized by a progressive age-related loss of muscle tissue, a process known as sarcopenia. There is a reduction in the number and size of muscle fibers, especially the fast-twitch fibers involved in speed and strength. As indicated by research from cross-sectional studies, muscle strength (as measured by maximum force) reaches a peak in the 20s and 30s, remains at a plateau until the 40s to 50s, and then declines at a faster rate of 12 to 15% per decade (Kostka, 2005), with more pronounced decreases, at least cross-sectionally, for men. Muscular endurance (as measured by isometric strength) is, however, generally maintained throughout adulthood (Lavender & Nosaka, 2007). […] The loss of muscle mass brings with it a set of negative consequences including increased risk of falling, limitations in mobility, and reduced quality of everyday life. Unfortunately, sarcopenia can become part of a vicious cycle because the greater the loss of muscle mass, the greater the difficulty in undertaking exercise, causing an exacerbation of muscle loss and further weakening (Lang et al., 2009). […]

Bone is living tissue that constantly reconstructs itself through a process of bone remodeling in which old cells are destroyed and replaced by new cells. The general pattern of bone development in adulthood involves an increase in the rate of bone destruction compared to renewal and greater porosity of the calcium matrix, leading to loss of bone mineral content. […] Estimates of the decrease in bone mineral content over adulthood are about .5% per year for men and 1% per year for women (Emaus, Berntsen, Joakimsen, & Fonnebo, 2006). Further weakening occurs due to microcracks that develop in response to stress placed on the bones (Diab, Condon, Burr, & Vashishth, 2006). Part of the older bone’s increased susceptibility to fracture can be accounted for by a loss of collagen, which reduces the bone’s flexibility when pressure is put upon it (Saito & Marumo, 2009). […]

Cardiovascular efficiency is indexed by aerobic capacity, the maximum amount of oxygen that can be delivered through the blood, and cardiac output, the amount of blood that the heart pumps perminute. Both indices decline consistently at a rate of about 10% per decade from age 25 and up so that the average 65-year-old has 40% lower cardiovascular efficiency than the young adult (Betik & Hepple, 2008). The decline is more pronounced in males than females (Goldspink et al., 2009). Maximum heart rate, the heart rate achieved at the point of maximum oxygen consumption, also shows a linear decrease across the years of adulthood. Declines in aerobic capacity occur even in highly trained athletes, but those who continue to exercise at a high level of intensitymaintain their aerobic capacity longer than non-athletes (Tanaka&Seals, 2003). […] With regard to aerobic functioning, exercise is one of the best ways you can slow down the rate of your body’s aging process. […]

Approximately 30% of all adults 65 and older suffer from urge incontinence, a form of urinary incontinence in which the individual experiences a sudden need to urinate, and often results in urine leakage. Stress incontinence involves loss of urine experienced during exertion. The prevalence of daily incontinence ranges from 12% in women 60 to 64 years old to 21% in women 85 years old or older […] A variety of treatments are available to counteract incontinence, but because people often mistakenly assume that bladder dysfunction is a normal part of aging, they are less likely to seek active treatment. In one study of more than 7.2 million patients diagnosed with overactive bladder, 76% went untreated (Helfand, Evans,&McVary, 2009). Medications such as tolderodine (Detrol LA) are becoming increasingly available to help control bladder problems. […]

Although men do not experience a loss of sexual function comparable to the menopause (despite what you might hear about the ‘‘male menopause’’), men undergo andropause, which refers to age-related declines in the male sex hormone testosterone. The decline in testosterone is equal to 1% per year after the age of 40, a decrease observed in longitudinal as well as cross-sectional studies (Feldman et al., 2002). The term ‘‘late-onset hypogonadism’’ or ‘‘age-associated hypogonadism’’ has begun to replace the term andropause, although all three terms are currently in use. […] Erectile dysfunction (ED), a condition in which a man is unable to achieve an erection sustainable for intercourse, is estimated to increase with age in adulthood, from a rate of 31% among men 57–65 to 44% of those 65 and older. ED is related to health problems in older men, including metabolic syndrome (Borges et al., 2009). […]

Normal aging seems to have major effects on the prefrontal cortex, the area of the brain most involved in planning and the encoding of information into long-term memory, as well as in the temporal cortex, involved in auditory processing (Fjell et al., 2009). The hippocampus, the structure in the brain responsible for consolidating memories, becomes smaller with increasing age, although this decline is more pronounced in abnormal aging such as in Alzheimer’s disease (Zhang et al., 2010). […]

Most people require some form of corrective lenses by the time they reach their 50s or 60s. Presbyopia, or loss of the ability to focus vision on near objects, is the primary culprit for the need for reading glasses, and is the visual change that most affects people in midlife and beyond.
Presbyopia is caused by a thickening and hardening of the lens, the focusing mechanism of the eye (Sharma & Santhoshkumar, 2009). As a result, the lens cannot adapt its shape when needed to see objects up close to the face. By the age of 50, presbyopia affects the entire population. Treatment for the cause of presbyopia does not exist, and although bifocals were the only correction since the time of Benjamin Franklin (who invented them) newer multifocal contact lenses are increasingly becoming available on the market (Woods, Woods, & Fonn, 2009). Though you cannot cure presbyopia, you may be able to alter its onset because lifestyle habits seem to affect the rate at which the presbyopic aging process occurs. For example, smoking accelerates the aging of the lens (Kessel, Jorgensen, Glumer, & Larsen, 2006).
Older adults are also likely to experience the loss of visual acuity, or the ability to see details at a distance. The level of acuity in an 85-yearold individual is approximately 80% less than that of a person in their 40s. […]

Loss of balance is one of the main factors responsible for falls in older adults (Dickin, Brown, & Doan, 2006). In 2007 alone, more than 15,800 people 65 and older were known to have died directly from injuries related to falls (Kung, Hoyert, Xu, & Murphy, 2008); 1.8 million were treated in emergency departments for fall-related nonfatal injuries, and about 460,000 of these people were hospitalized (Stevens, Ryan, & Kresnow, 2006). […]

Smell and taste belong to the chemical sensing system referred to as chemosensation. The sensory receptors in these systems are triggered when molecules released by certain substances stimulate special cells in the nose, mouth, or throat. Despite the fact that the olfactory receptors constantly replace themselves, the area of the olfactory epithelium shrinks with age, and ultimately the total number of receptors becomes reduced throughout the adult years. At birth, the olfactory epithelium covers a wide area of the upper nasal cavities, but by the 20s and 30s, its area has started to shrink noticeably.
Approximately one third of all older adults suffer some form of olfactory impairment (Shu et al., 2009) with almost half of those 80 years and older having virtually no ability to smell at all (Lafreniere & Mann, 2009). The loss of olfactory receptors reflects intrinsic changes associated with the aging process, as well as damage caused by disease, injury, and exposure to toxins. Research suggests that these environmental toxins may play a larger role in olfactory impairment than changes due to the aging process. […]

A sedentary lifestyle is the first major risk factor for heart disease. The relationship between leisure activity and heart disease is well established (Yung et al., 2009), with estimates ranging from a 24% reduction in the risk of myocardial infarction among non-strenuous exercisers to a 47% reduced risk among individuals engaging in a regular pattern of strenuous exercise (Lovasi et al., 2007). As it happens, the majority of adults at highest risk for heart disease (i.e., those 75 and older) are the least likely to exercise. Only about 36% of people 65 to 74 and 16% of those 75 and older engage in vigorous leisure activity (National Health Interview Survey, 2009). […] Approximately one fifth of all adults in the United States are current smokers. The rates of current smokers decrease across age groups of adults to 10% of those 65 and older (National Health Interview Survey, 2009). […]

In 2009, it was estimated that nearly 1.5 million Americans received a diagnosis of cancer (not including skin cancer or noninvasive cancers) and that about 10.5 million are living with the disease. The lifetime risk of developing cancer is about 1 in 2 for men and 1 in 3 for women (American Cancer Society, 2009). […] All cancer is genetically caused in the sense that it reflects damage to the genes that control cell replication. […this is actually, I think, a very good way to put it.] […]

A nationwide study of over 900,000 adults in the United States who were studied prospectively (before they had cancer) from 1982 to 1998 played an important role in identifying the role of diet. During this period of time, there were more than 57,000 deaths within the sample from cancer. The people with the highest BMIs had death rates from cancer that were 52% higher for men and 62% higher for women compared with men and women of normal BMI. The types of cancer associated with higher BMIs included cancer of the esophagus, colon and rectum, liver, gallbladder, pancreas, and kidney. Significant trends of increasing risk with higher BMIs were observed for death from cancers of the stomach and prostate in men and for death from cancers of the breast, uterus, cervix, and ovary in women (Calle, Rodriguez, Walker-Thurmond, & Thun, 2003). We can conclude from this research that maintaining a low BMI is a critical preventive step in lowering your risk of cancer.

In addition to BMI, eating specific foods seems to play a role in cancer prevention. Stomach cancer is more common in parts of the world—such as Japan, Korea, parts of Eastern Europe, and Latin America—in which people eat foods that are preserved by drying, smoking, salting, or pickling. By contrast, fresh foods, especially fresh fruits and vegetables, may help protect against stomach cancer. Similarly, the risk of developing colon cancer is thought to be higher in people whose diet is high in fat, low in fruits and vegetables, and low in highfiber foods such as whole-grain breads and cereals. […]

It is estimated that 8 million women and 2 million men in the United States suffer from osteoporosis (Sweet, Sweet, Jeremiah, & Galazka, 2009). Women are at higher risk than men because they have lower bone mass in general but nevertheless, osteoporosis is a significant health problem in men. Rates of osteoporosis-related bone fracture are equivalent to the rates of myocardial infarction (Binkley, 2009). Women vary by race and ethnicity in their risk of developing osteoporosis; White and Asian women have the highest risk, whereas Blacks and Hispanics the lowest. In addition, women who have small bone structures and are underweight have a higher risk for osteoporosis than heavier women. […]

According to the World Health Organization, the number of people suffering from diabetes worldwide is approximately 171 million in 2010, a number that will double by 2030. […]

Approximately 20% of cases of dementia are due to cerebrovascular disease (Knopman, 2007). […] In vascular dementia, progressive loss of cognitive functioning occurs as the result of damage to the arteries supplying the brain. Dementia can follow a stroke, in which case it is called acute onset vascular dementia, but the most common form of vascular dementia is multi-infarct dementia or MID, caused by transient ischemic attacks. In this case, a number of minor strokes (‘‘infarcts’’) occur in which blood flow to the brain is interrupted by a clogged or burst artery. Each infarct is too small to be noticed, but over time, the progressive damage caused by the infarcts leads the individual to lose cognitive abilities. There are important differences between MID and Alzheimer’s disease. The development of MID tends to be more rapid than Alzheimer’s disease, and personality changes are less pronounced. The higher the number of infarcts, the greater the decline in cognitive functioning (Saczynski et al., 2009). […]

People who develop Parkinson’s disease show a variety of motor disturbances, including tremors (shaking at rest), speech impediments, slowing of movement, muscular rigidity, shuffling gait, and postural instability or the inability to maintain balance. Dementia can develop during the later stages of the disease, and some people with Alzheimer’s disease develop symptoms of Parkinson’s disease. Patients typically survive 10 to 15 years after symptoms appear.”

December 19, 2012 - Posted by | biology, books, data, diabetes, medicine

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