Cafestol, C₂₀H₂₈O₃, is a compound, specifically a diterpene alcohol, found in coffee beans. It is extracted during the coffee-brewing process and may be present in coffee beverages, depending on the preparation method. Consumption of cafestol in coffee has been shown to produce both positive and negative health effects. See also: Coffee; Terpene

The cancer death rate in the United States has fallen by 27% since 1991. According to the American Cancer Society, which compiled the data over a 25-year period from 1991 to 2016, a total of 2.6 million fewer individuals have died from cancer in the United States. This remarkable decrease, which is a trend observed in both males and females, is attributed to a number of factors. The most notable factors are (1) the continual awareness and dissemination of information about the link between lung cancer and tobacco smoking, resulting in large reductions in the number of individuals who smoke; (2) advancements in early screening and detection methodologies; and (3) more effective cancer treatments and chemotherapies. In addition, there has been overall increased awareness on the part of individuals to avoid exposure to a multitude of other cancer risk factors. For example, individuals are more prone than those in the past to avoid certain carcinogens in their diet and to limit their exposure to the Sun's ultraviolet (UV) rays in order to maintain a healthier lifestyle. See also: Cancer; Chemotherapy and other antineoplastic drug treatments; Death; Nutrition; Oncology; Tobacco; Ultraviolet radiation (biology)

According to new research, young adults who reported higher stress during their childhood and teenage years to adulthood are more likely to suffer high blood pressure, obesity, or other cardiometabolic risk factors than their less-stressed peers. Known cardiometabolic risk factors include age, sex, family history, hypertension, smoking, dysglycemia (abnormality in blood sugar stability), and dyslipidemia (the imbalance of lipids such as cholesterol, triglycerides, LDLs, and HDLs in the body). Now, a group of researchers has found a new risk factor: childhood stress. See also: Cholesterol; Lipoprotein; Triglyceride (triacylglycerol)

Colorectal cancer (also termed colon or bowel cancer) is the third most prevalent type of cancer both in men and in women, taking the lives of approximately 400,000 people annually worldwide (including 50,000 people per year in the United States). It results when tumors form in the lining of the large intestine's colon or rectum. Since the year 2000, the number of cases and mortality rates of patients having colorectal cancer have risen dramatically among young and middle-aged adults in the United States. Specifically, in adults younger than age 50, the incidence rate of colorectal cancer has increased by 22%, with an accompanying 13% increase in the death rate from this condition. These statistics are surprising because the rates among persons more than 50 years of age have been dropping, predominantly because of their adoption of healthier lifestyle habits (such as smoking less and eating less red meat) and improvements in medical screening and treatment protocols. Thus, the rise of colorectal cancer in the younger population is a troubling shift. See also: Cancer; Colon; Digestive system; Gastrointestinal tract disorders; Intestine; Oncology; Tumor

Sickle cell disease, also termed sickle cell anemia, is a genetic disorder in which hypoxia, or oxygen deprivation, causes red blood cells (erythrocytes) to assume a rigid sickle shape, blocking blood flow within blood vessels. The disease results from a single nucleotide mutation in the gene for beta-globin (β-globin), which causes production of an abnormal form of hemoglobin—an oxygen-carrying protein in red blood cells. Millions of people worldwide suffer from sickle cell disease, enduring lifelong anemia, as well as possible organ damage and potentially early death. The abnormal rigidity of sickle cells also causes painful obstruction of small blood vessels, and recurrent painful episodes are frequent in the absence of proper therapies. The most common treatment options include analgesics for pain, antibiotics for fighting infections, transfusions for episodes of severe anemia, and hydroxyurea (an oral medication that hinders formation of sickle-shaped red blood cells and reduces inflammation). See also: Anemia; Blood; Blood vessel; Hemoglobin; Human genetics; Mutation; Nucleotide; Sickle cell disease

Macular degeneration is the most prevalent cause of vision impairment and loss among people aged 55 years and older. Also termed age-related macular degeneration (AMD), this serious eye condition damages the macula, which is the most sensitive part of the retina of the eye. Located near the center of the retina, the macula consists of millions of light-sensing cells that provide sharp, central vision, enabling objects that are straight ahead of the eye to be seen. Normally, photoreceptors in the retina convert light entering the eye into electrical signals that are sent through the optic nerve to the brain, which interprets them as visual images. However, when the macula deteriorates and undergoes atrophy, the center of a person's field of view appears distorted, blurry, or dark, which hampers or eliminates fine vision, including the detailed vision necessary for such important activities as reading a book, threading a needle, and recognizing faces. See also: Brain; Color vision; Eye (vertebrate); Eye disorders; Light; Perception; Photoreception; Vision; Visual impairment

Osteoprotegerin (OPG) is a protein that plays a central role in the regulation of bone mass. Also known as osteoclastogenesis inhibitory factor (OCIF), this naturally occurring protein [a soluble decoy receptor protein that belongs to the tumor necrosis factor (TNF) receptor superfamily] inhibits both the formation of osteoclasts (bone-resorbing cells) and the activity of these cells when they are mature. Because of this dual function, osteoprotegerin is believed to have great potential as a therapeutic agent for a number of bone and joint disorders, including rheumatoid arthritis, cancer-induced bone diseases, and osteoporosis (a metabolic condition in which decreases in bone mass and reductions in the amount of bone tissue increase the likelihood of fracture). In particular, because osteoprotegerin is able to block the development of osteoclasts, the administration of this protein is seen as a possible means to halt age-associated bone resorption and loss, to protect bone strength, and to decrease the chance of bone fracture. See also: Arthritis; Bone; Bone disorders; Cancer; Connective tissue; Joint disorders; Oncology; Osteoporosis; Protein

The field of vaccination has been enhanced significantly by the successful development of two approved vaccines based on messenger RNA (mRNA) technologies. Prior to the COVID-19 pandemic that spread from China in 2019 to the rest of the world in 2020, no mRNA vaccine had ever been approved for use against any disease in humans. However, in late 2020 and early 2021, two mRNA vaccines (developed independently by pharmaceutical and biotechnology companies Pfizer/BioNTech and Moderna) to prevent COVID-19 were approved for emergency use in the United States, Canada, the European Union, and elsewhere. Now, mRNA vaccination strategies are being fast-tracked to combat other diseases. Most notably, researchers have designed an mRNA vaccine to treat and prevent acute disseminated encephalomyelitis (ADEM)—an autoimmune disease similar to multiple sclerosis—in mice. In experimental mouse models, this vaccine was able to prevent encephalomyelitis, or inflammation of the brain and spinal cord. In addition, in mice with early-stage ADEM, the vaccine lessened the onset and severity of the disease and halted disease progression, allowing restoration of motor function. See also: Inflammation; Multiple sclerosis; Ribonucleic acid (RNA); Searching for a COVID-19 vaccine; Vaccination

Occurring in mammary glands and closely associated tissues, breast cancer is the most common cancer observed in women. For example, in the United States, approximately 1 in 8 women (about 12%) will develop invasive breast cancer over the course of her lifetime. In terms of numbers, more than 276,000 new cases of invasive breast cancer are predicted to be detected among women in the United States in the year 2020. See also: Breast cancer and other breast disorders; Cancer; Oncology

Marfan syndrome (or Marfan's syndrome) is a connective-tissue disorder that manifests through distinctive skeletal and ocular changes as well as congenital heart disease. A mutation in the gene (FBN1) that normally directs the body to make fibrillin-1 (an important connective-tissue protein) causes this condition. When functioning properly, fibrillin-1 is transported to the extracellular matrix and helps to form microfibrils and other elastic fibers in cells that allow blood vessels, ligaments, and the skin to stretch. These fibers also provide rigidity to bones and other supportive elements of the nervous system, muscular system, and eyes. When the FBN1 gene is defective, the body's levels of fibrillin-1 are dramatically low. Conversely, levels of activity for transforming growth factor beta (TGF-β), a protein that fibrillin-1 usually suppresses, become unusually high. This abnormality leads to major problems in the body's connective tissues. The excess TGF-β reduces the elasticity of many tissues, thereby weakening them, but also enabling them to grow excessively. The areas of the body most affected by Marfan syndrome are the heart, blood vessels, eyes, and skeleton. The nervous system, lungs, and skin may also be affected. See also: Connective tissue; Gene; Growth factor; Histology; Mutation; Protein