Chronic Constipation in Black Adults: Causes and Red Flags

Chronic constipation has formal diagnostic criteria, a short list of common causes, and treatments with real trial evidence behind them. Most adults who have it are taking a drug that causes it, living with an untreated thyroid or metabolic condition, or have a pelvic floor that will not relax on command. Laxatives fix some of those and none of the others. And one pattern, new constipation after 45, belongs in a colonoscopy suite rather than a pharmacy aisle.

The clinical standard is the Rome IV criteria: at least two of the following in the past three months, with symptoms starting at least six months earlier. Straining, lumpy or hard stools, a sense of incomplete evacuation, a sense of anorectal blockage, or needing manual maneuvers, each during more than 25% of bowel movements. Or fewer than three spontaneous bowel movements per week. Loose stools have to be rare without laxatives, and the criteria for irritable bowel syndrome cannot be met.

Only one of those six items is about frequency. You can go every day and still meet the definition if you are straining, passing hard pellets, or leaving the bathroom feeling unfinished.

Roughly 14% of adults worldwide have chronic idiopathic constipation. The established risk factors are female sex, older age, and lower socioeconomic status. Whether it is more common among Black adults is not settled evidence, and we will not invent a number for it. The toll is documented: in a Philadelphia case-control study of 102 middle-aged Black adults with functional constipation and 100 matched controls, SF-36 mental health scores were lower in the constipated group (43.6 versus 49.9).

Drug-induced constipation is the cause people miss most often, because the drug got started for something unrelated and the timing gets lost. The classes that do it, per the National Institute of Diabetes and Digestive and Kidney Diseases:

• Opioid pain medicines. These act on receptors in the bowel wall itself, so tolerance never develops. The constipation lasts as long as the prescription does.
• Iron supplements, often taken for an anemia never fully worked up.
• Calcium channel blockers, particularly nifedipine and verapamil.
• Anticholinergics and antispasmodics, including bladder medications, older antihistamines, and Parkinson disease drugs.
• Tricyclic antidepressants such as amitriptyline and nortriptyline.
• Aluminum and calcium-containing antacids, diuretics, and some anticonvulsants.

A medication review that covers supplements and over-the-counter products, not only prescriptions, often turns up an agent that can be swapped or stopped. For opioid-induced constipation, the American Gastroenterological Association recommends standard laxatives first and reserves the prescription blockers (naloxegol, methylnaltrexone, naldemedine) for people in whom those fail.

Hypothyroidism and diabetes. An underactive thyroid slows gut transit, and long-standing diabetes damages the autonomic nerves that drive the bowel. Both are diagnosed with a blood test that takes one visit to order.

Pelvic floor dysfunction, also called dyssynergic defecation. This is the one that gets missed for years. The pelvic floor and anal sphincter are supposed to relax as you push. In dyssynergia they contract instead, so the harder you push the more tightly the exit closes. As many as 40% of patients investigated for chronic constipation have it, and laxatives often fail because the stool is already soft and the problem is mechanical. The tell is straining against soft stool, pressing around the rectum or vagina to pass anything, or feeling a blockage at the exit.

It is diagnosed with anorectal manometry and a balloon expulsion test, and treated with pelvic floor biofeedback. In randomized trials, 70% to 80% of patients whose constipation resisted standard therapy improved substantially, and 55% to 82% held that improvement long-term. Biofeedback beat laxatives, sham therapy, and placebo head-to-head.

IBS with constipation. If abdominal pain is tied to your bowel movements and has been for months, the diagnosis may be IBS-C rather than chronic idiopathic constipation. The treatments overlap but are not identical. See our guide to IBS in Black adults.

Fiber, but the right kind. The USDA recommends 25 g per day for women and 38 g for men; average adult intake runs around 16 g. Type matters. In a systematic review of chronic constipation trials, soluble fiber improved global symptoms in 86.5% of patients versus 47.4% on placebo, reduced straining (55.6% versus 28.6%), and raised stool frequency to 3.8 per week from a baseline of 2.9. Evidence for insoluble fiber was inconsistent. Psyllium has the clearest support. Increase by about 5 g per week, not all at once.

Polyethylene glycol 3350 is the first-line drug. Sold as Miralax and as generics, typically 17 g per day, roughly $13 a bottle. The joint American Gastroenterological Association and American College of Gastroenterology guideline gives it a strong recommendation, and a Cochrane review found it superior to lactulose. Response can take up to 72 hours, so give it more than one night.

The fear of stimulant laxatives is largely unfounded. The belief that senna or bisacodyl damages the colon, destroys nerves, or creates dependence is a long-standing misconception in the literature, not a finding. The joint guideline strongly recommends bisacodyl and sodium picosulfate for short-term or rescue use, with a conditional recommendation for senna. In a randomized trial, four weeks of bisacodyl raised spontaneous bowel movements from 1.1 per week to 5.2, against 1.9 on placebo. Long-term daily use has not been formally studied, a gap in the evidence rather than a demonstrated harm.

Prescription drugs come after, not before. Linaclotide, plecanatide, and prucalopride carry strong guideline recommendations for people who fail fiber and osmotic laxatives. They run several hundred dollars a month at retail, and no evidence shows they beat standard laxatives as a starting point.

The honest version first: constipation by itself does not indicate colorectal cancer. A systematic review and meta-analysis of observational studies found no increased prevalence of colorectal cancer in patients with constipation alone, and routine colonoscopy is not recommended without alarm features.

The alarm features that warrant a colonoscopy referral: unintentional weight loss, rectal bleeding or blood in the stool, unexplained anemia, fatigue, a change in bowel habits, narrowing of the stool, and a family history of colorectal cancer or inflammatory bowel disease. New constipation at or after 45 is its own trigger, because the US Preventive Services Task Force and the American College of Gastroenterology both moved the average-risk screening start to 45 in 2021.

The stakes are specific. Colorectal cancer incidence among non-Hispanic Black men runs 50.1 cases per 100,000 and among non-Hispanic Black women 37.1 per 100,000 (2019-2023 SEER data). Death rates are 20.5 and 13.2 per 100,000 respectively (2020-2024). It is one of the few cancers screening can prevent outright, by removing polyps before they turn.

Coverage in the newly eligible age band is thin. In 2022, the first full year after the age change, 29.8% of US adults aged 45 to 49 were up to date on colorectal cancer screening. Among non-Hispanic Black adults aged 45 to 75 the figure was 65.0%. A large share of people who show up with new constipation in their late forties have never been screened. Our guide to colon cancer screening for Black adults covers the test options.

Walk in with three things: a complete medication and supplement list; a two-week bowel diary noting frequency, stool form, straining, and whether you needed manual help; and what has already failed, with doses and duration. "Fiber did not work" and "30 g of psyllium daily for six weeks did not work" lead to different next steps.

Ask for four things by name. A thyroid panel and a glucose or A1c check. A digital rectal examination, a reliable office test for the pelvic floor problem above. A referral for anorectal manometry and a balloon expulsion test if osmotic laxatives have failed. And confirmation of whether you are due for colorectal cancer screening.

You can find a Black gastroenterologist or primary care clinician in our directory. Bowel symptoms are among the easiest complaints to get brushed off, and the visit goes differently when you are not spending it establishing that the problem is real.