Insulin Resistance & Pre-Diabetes

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Insulin resistance and prediabetes occur when your body doesn’t use insulin well.

What is insulin?

Insulin is a hormone made by the pancreas that helps glucose in your blood enter cells in your muscle, fat, and liver, where it’s used for energy. Glucose comes from the food you eat. The liver also makes glucose in times of need, such as when you’re fasting. When blood glucose, also called blood sugar, levels rise after you eat, your pancreas releases insulin into the blood. Insulin then lowers blood glucose to keep it in the normal range.

What is insulin resistance?

Insulin resistance is when cells in your muscles, fat, and liver don’t respond well to insulin and can’t easily take up glucose from your blood. As a result, your pancreas makes more insulin to help glucose enter your cells. As long as your pancreas can make enough insulin to overcome your cells’ weak response to insulin, your blood glucose levels will stay in the healthy range.

What is prediabetes?

Prediabetes means your blood glucose levels are higher than normal but not high enough to be diagnosed as diabetes. Prediabetes usually occurs in people who already have some insulin resistance or whose beta cells in the pancreas aren’t making enough insulin to keep blood glucose in the normal range. Without enough insulin, extra glucose stays in your bloodstream rather than entering your cells. Over time, you could develop type 2 diabetes.

How common is prediabetes?

More than 84 million people ages 18 and older have prediabetes in the United States.1 That’s about 1 out of every 3 adults.

Who is more likely to develop insulin resistance or prediabetes?

People who have genetic or lifestyle risk factors are more likely to develop insulin resistance or prediabetes. Risk factors include

  • overweight or obesity
  • age 45 or older
  • a parent, brother, or sister with diabetes
  • African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander American ethnicity
  • physical inactivity
  • health conditions such as high blood pressure and abnormal cholesterol levels
  • a history of gestational diabetes
  • a history of heart disease or stroke
  • polycystic ovary syndrome, also called PCOS

People who have metabolic syndrome—a combination of high blood pressure, abnormal cholesterol levels, and large waist size—are more likely to have prediabetes.

Along with these risk factors, other things that may contribute to insulin resistance include

Although you can’t change risk factors such as family history, age, or ethnicity, you can change lifestyle risk factors around eating, physical activity, and weight. These lifestyle changes can lower your chances of developing insulin resistance or prediabetes.

An overweight Hispanic woman smiling
Being overweight or having obesity are risk factors for developing insulin resistance or prediabetes.

What causes insulin resistance and prediabetes?

Researchers don’t fully understand what causes insulin resistance and prediabetes, but they think excess weight and lack of physical activity are major factors.

Excess weight

Experts believe obesity, especially too much fat in the abdomen and around the organs, called visceral fat, is a main cause of insulin resistance. A waist measurement of 40 inches or more for men and 35 inches or more for women is linked to insulin resistance. This is true even if your body mass index (BMI) falls within the normal range. However, research has shown that Asian Americans may have an increased risk for insulin resistance even without a high BMI.

Researchers used to think that fat tissue was only for energy storage. However, studies have shown that belly fat makes hormones and other substances that can contribute to chronic, or long-lasting, inflammation in the body. Inflammation may play a role in insulin resistance, type 2 diabetes, and cardiovascular disease.

Excess weight may lead to insulin resistance, which in turn may play a part in the development of fatty liver disease.

Physical inactivity

Not getting enough physical activity is linked to insulin resistance and prediabetes. Regular physical activity causes changes in your body that make it better able to keep your blood glucose levels in balance.

What are the symptoms of insulin resistance and prediabetes?

Insulin resistance and prediabetes usually have no symptoms. Some people with prediabetes may have darkened skin in the armpit or on the back and sides of the neck, a condition called acanthosis nigricans. Many small skin growths called skin tags often appear in these same areas.

Even though blood glucose levels are not high enough to cause symptoms for most people, a few research studies have shown that some people with prediabetes may already have early changes in their eyes that can lead to retinopathy. This problem more often occurs in people with diabetes.

How do doctors diagnose insulin resistance and prediabetes?

Doctors use blood tests to find out if someone has prediabetes, but they don’t usually test for insulin resistance. The most accurate test for insulin resistance is complicated and used mostly for research.

A health care professional draws blood from a person’s arm.
Doctors use blood tests to find out if someone has prediabetes.

Doctors most often use the fasting plasma glucose (FPG) test or the A1C test to diagnose prediabetes. Less often, doctors use the oral glucose tolerance test (OGTT), which is more expensive and not as easy to give.

The A1C test reflects your average blood glucose over the past 3 months. The FPG and OGTT show your blood glucose level at the time of the test. The A1C test is not as sensitive as the other tests. In some people, it may miss prediabetes that the OGTT could catch. The OGTT can identify how your body handles glucose after a meal—often before your fasting blood glucose level becomes abnormal. Often doctors use the OGTT to check for gestational diabetes, a type of diabetes that develops during pregnancy.

People with prediabetes have up to a 50 percent chance of developing diabetes over the next 5 to 10 years. You can take steps to manage your prediabetes and prevent type 2 diabetes.

The following test results show Prediabetes2

  • A1C—5.7 to 6.4 percent
  • FPG—100 to 125 mg/dL (milligrams per deciliter)
  • OGTT—140 to 199 mg/dL

You should be tested for prediabetes if you are overweight or have obesity and have one or more other risk factors for diabetes, or if your parents, siblings, or children have type 2 diabetes. Even if you don’t have risk factors, you should start getting tested once you reach age 45.

If the results are normal but you have other risk factors for diabetes, you should be retested at least every 3 years.2

How can I prevent or reverse insulin resistance and prediabetes?

Physical activity and losing weight if you need to may help your body respond better to insulin. Taking small steps, such as eating healthier foods External link and moving more to lose weight, can help reverse insulin resistance and prevent or delay type 2 diabetes in people with prediabetes.

An African American man walking briskly in a park
Physical activity can help prevent or reverse insulin resistance and prediabetes.

The National Institutes of Health-funded research study, the Diabetes Prevention Program (DPP), showed that for people at high risk of developing diabetes, losing 5 to 7 percent of their starting weight helped reduce their chance of developing the disease.3 That’s 10 to 14 pounds for someone who weighs 200 pounds. People in the study lost weight by changing their diet and being more physically active.

The DPP also showed that taking metformin NIH external link, a medicine used to treat diabetes, could delay diabetes. Metformin worked best for women with a history of gestational diabetes, younger adults, and people with obesity. Ask your doctor if metformin might be right for you.

Making a plan, tracking your progress, and getting support from your health care professional, family, and friends can help you make lifestyle changes that may prevent or reverse insulin resistance and prediabetes. You may be able to take part in a lifestyle change program as part of the National Diabetes Prevention Program External link.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you NIH external link.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov NIH external link.

References

Body Mass Index (BMI)

BMI is a measurement of body weight relative to height. Adults aged 20 or older can use the BMI table below to find out whether they are normal weight, overweight, obese, or extremely obese. To use the table, follow these steps:

  • Find the person's height in the left-hand column.
  • Move across the row to the number closest to that person's weight.
  • Check the number at the top of that column.

The number at the top of the column is the person's BMI. The words above the BMI number indicate whether the person is normal weight, overweight, obese, or extremely obese. People who are overweight, obese, or extremely obese should consider talking with a doctor about ways to lose weight to reduce the risk of diabetes.

The BMI table has certain limitations. It may overestimate body fat in athletes and others who have a muscular build and underestimate body fat in older adults and others who have lost muscle. BMI for children and teens must be determined based on age and sex in addition to height and weight. Information about BMI in children and teens, including a BMI calculator, is available from the Centers for Disease Control and Prevention (CDC) at www.cdc.gov/nccdphp/dnpa/bmi. The CDC website also has a BMI calculator for adults.

Body Mass Index Table

Printer-friendly version (pdf)

Body Mass Index Table 1 of 2

 

Normal

Overweight

Obese

BMI 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Height
(inches)
Body Weight (pounds)
58 91 96 100 105 110 115 119 124 129 134 138 143 148 153 158 162 167
59 94 99 104 109 114 119 124 128 133 138 143 148 153 158 163 168 173
60 97 102 107 112 118 123 128 133 138 143 148 153 158 163 168 174 179
61 100 106 111 116 122 127 132 137 143 148 153 158 164 169 174 180 185
62 104 109 115 120 126 131 136 142 147 153 158 164 169 175 180 186 191
63 107 113 118 124 130 135 141 146 152 158 163 169 175 180 186 191 197
64 110 116 122 128 134 140 145 151 157 163 169 174 180 186 192 197 204
65 114 120 126 132 138 144 150 156 162 168 174 180 186 192 198 204 210
66 118 124 130 136 142 148 155 161 167 173 179 186 192 198 204 210 216
67 121 127 134 140 146 153 159 166 172 178 185 191 198 204 211 217 223
68 125 131 138 144 151 158 164 171 177 184 190 197 203 210 216 223 230
69 128 135 142 149 155 162 169 176 182 189 196 203 209 216 223 230 236
70 132 139 146 153 160 167 174 181 188 195 202 209 216 222 229 236 243
71 136 143 150 157 165 172 179 186 193 200 208 215 222 229 236 243 250
72 140 147 154 162 169 177 184 191 199 206 213 221 228 235 242 250 258
73 144 151 159 166 174 182 189 197 204 212 219 227 235 242 250 257 265
74 148 155 163 171 179 186 194 202 210 218 225 233 241 249 256 264 272
75 152 160 168 176 184 192 200 208 216 224 232 240 248 256 264 272 279
76 156 164 172 180 189 197 205 213 221 230 238 246 254 263 271 279 287

 

Body Mass Index Table 2 of 2

 

Obese

Extreme Obesity

BMI

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

Height
(inches)

Body Weight (pounds)

58

172

177

181

186

191

196

201

205

210

215

220

224

229

234

239

244

248

253

258

59

178

183

188

193

198

203

208

212

217

222

227

232

237

242

247

252

257

262

267

60

184

189

194

199

204

209

215

220

225

230

235

240

245

250

255

261

266

271

276

61

190

195

201

206

211

217

222

227

232

238

243

248

254

259

264

269

275

280

285

62

196

202

207

213

218

224

229

235

240

246

251

256

262

267

273

278

284

289

295

63

203

208

214

220

225

231

237

242

248

254

259

265

270

278

282

287

293

299

304

64

209

215

221

227

232

238

244

250

256

262

267

273

279

285

291

296

302

308

314

65

216

222

228

234

240

246

252

258

264

270

276

282

288

294

300

306

312

318

324

66

223

229

235

241

247

253

260

266

272

278

284

291

297

303

309

315

322

328

334

67

230

236

242

249

255

261

268

274

280

287

293

299

306

312

319

325

331

338

344

68

236

243

249

256

262

269

276

282

289

295

302

308

315

322

328

335

341

348

354

69

243

250

257

263

270

277

284

291

297

304

311

318

324

331

338

345

351

358

365

70

250

257

264

271

278

285

292

299

306

313

320

327

334

341

348

355

362

369

376

71

257

265

272

279

286

293

301

308

315

322

329

338

343

351

358

365

372

379

386

72

265

272

279

287

294

302

309

316

324

331

338

346

353

361

368

375

383

390

397

73

272

280

288

295

302

310

318

325

333

340

348

355

363

371

378

386

393

401

408

74

280

287

295

303

311

319

326

334

342

350

358

365

373

381

389

396

404

412

420

75

287

295

303

311

319

327

335

343

351

359

367

375

383

391

399

407

415

423

431

76

295

304

312

320

328

336

344

353

361

369

377

385

394

402

410

418

426

435

443

Source: Adapted from Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report, National Institutes of Health, 1998.

 

Tags

Diabetes Health