Excess Body Weight , Joint Pain, & Arthritis

Belly fat is an engine of joint inflammation.

The most important control you have over your joint pain is controlling your weight.

These are exciting concepts, because they point to an element of control over your joints that is well within your personal reach.

To understand why this is important, we need to look at a couple of shocking statistics about how dramatically weight affects the joints.

If you are one pound over weight, you increase the force of the load on your knees by about 4,800 pounds for every one mile you walk.
If you are ten pounds over weight, you increase the force of the load on your knees by about 48,000 pounds for every mile you walk.

This is actually quite astounding. It means that the forces of excess weight just keep adding up. As you add more weight over more time, the demands on your joints just continue to grow. This is a bit like loading the trunk of your car with bags of sand or your pickup truck with a load of rock. Keep piling on the load and the vehicle sinks lower and lower. The shock absorbers and springs that support the car just keep groaning under the added weight. Pile up the loads over time and the shock absorbing supports wear out sooner. We can replace the shocks, springs, and struts. But we cannot easily replace the knee or the hip joint. So our response must be to get rid of the excess weight.

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We can also look at this by how weight affects the rate of osteoarthritis. For every 2 units of BMI (BMI=body mass index--about 12 pounds), osteoarthritis of the knee increased by 36 percent. Studies have also shown that, since weight gain gradually increases the stress on joints, the weight you gain the decade before you have OA symptoms, particularly in middle age, plays a big role in determining if you will develop osteoarthritis.

[March, LM, Bagga, H. Epidemiology of osteoarthritis in Australia. Med J Australia 2004;180(5 suppl): S6-S10.]

It is very important to understand this last statement—that being overweight may be one of the key factors the eventually leads you to develop osteoarthritis even if you do not yet have the disorder. This was made clear by researchers in England. They studied people over age 50 from three separate clinics over a period of three years. Those who were overweight at the beginning of the study (and who did not have arthritis at the study’s beginning) were more likely to develop osteoarthritis over the next three years. In other words, being overweight or obese actually predicted who would develop arthritis in just three years time.

This study is important because it suggests that you may be able to prevent osteoarthritis by losing excess weight before you develop arthritis. Looked at it in the negative, if you are overweight and you do not take steps to reduce your body weight, your likelihood of going on to develop osteoarthritis may be much higher.

[Jinks, C, Jordan, K, Croft, P. Disabling knee pain--another consequence of obesity: results from a prospective cohort study. BMC Public Health 2006;6:258.]

Other studies looking at obesity and osteoarthritis have shown that being overweight is linked to the progression of osteoarthritis. This means that excess weight can cause osteoarthritis to continually get worse. As body weight further increases, the progression of osteoarthritis accelerates, especially osteoarthritis of the knee.

[Reijman, M, Pols, HA, Bergink, AP, et al. Body mass index associated with onset and progression of osteoarthritis of the knee but not of the hip: the Rotterdam Study. Ann Rheum Dis. 2007;66(2):158-62.]

Women are at particular risk for developing osteoarthritis. Doctors at Oxford University studied 111 women between the ages of 36 to 40 and ages 50 to 55. After factoring out many possible risk factors, body mass index (BMI) was the strongest influence on who developed osteoarthritis. Those between the ages of 36 and 40 who had a BMI greater than 25 (those who were overweight) had a higher risk to developing osteoarthritis. One of the key findings, according to the authors, was that “being overweight before the age of 40 considerably increased the risk of subsequent symptomatic osteoarthritis in women.”

[Dawson, J, Juszczak, E, Thorogood, M, et al. An investigation of risk factors for symptomatic osteoarthritis of the knee in women using a life course approach. J Epidemiol Community Health 2003;57(10):823-30.]

These are all very important ideas to understand. It suggests that the joint pain you have right now, today, could be modified by reducing your body weight. That is a tremendous amount of control. It also suggests that if you are overweight today, but you don’t have joint pain right now, you could gain control over whether you develop osteoarthritis.

Obesity and Risk for Knee or Hip Replacement

[Harms, S, Larson, R, Sahmoun, AE, Beal, JR. Obesity increases the likelihood of total joint replacement surgery among younger adults. Int Orthop. 2007;31(1):23-6.]

Beyond osteoarthritis of the knee, there is now also evidence that being overweight can increase the risk of needing a hip replacement as well.

To summarize, studies have shown the following with regard to excess body weight and joint inflammation:

1) Excess body weight increases the risk of developing OA if you don’t already have OA
2) Excess body weight increases the speed of progression of OA if you already have OA
3) Excess body weight is linked to a greater risk of OA even in young people
4) Excess body weight increases the likelihood of having knee replacement surgery in old age
5) Excess body weight increases the likelihood of having knee replacement surgery even in young people
6) Being overweight before age 40 increases the risk of developing OA in the future

The effect of excess weight bearing down on joints is important, but it is not the only effect of excess weight. It is now clear that belly fat secretes a vast array of inflammatory molecules, which have tremendous joint-damaging potential. This is another reason Excess weight has another dramatic effect on joints, which get very little attention. This has to do with joint-damaging substances that are produced by fat cells.

See Belly Fat Fuels Joint Inflammation

[Manek, NJ, Hart, D, Spector, TD, MacGregor, AJ. The association of body mass index and osteoarthritis of the knee joint: an examination of genetic and environmental influences. Arthritis Rheum. 2003 Apr;48(4):1024-9.]

Calculate Your Body Mass Index

Body Mass Index (BMI), which is a number calculated from the ratio between a person's weight and height, provides a reliable indicator of body fatness for most people. It is used to screen for weight categories that may lead to health problems.

If you have a BMI reading of between 18.5 and 24, you are regarded as being of normal body weight. Below 18.5 is underweight.

A BMI reading of between 25 and 29.9 is regarded as being overweight. Between 30 and 34 is regarded as obese.

A reading between 30 and 34 is regarded as obese and over 34 as being very obese.

To use the table, find the appropriate height in the left-hand column labeled Height. Move across to the adjacent given weight (in pounds). The number at the top of the column is the BMI at that height and weight. Pounds have been rounded off.

BMI	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36
Height (inches)	Body Weight (pounds)
58	91	96	100	105	110	115	119	124	129	134	138	143	148	153	158	162	167	172
59	94	99	104	109	114	119	124	128	133	138	143	148	153	158	163	168	173	178
60	97	102	107	112	118	123	128	133	138	143	148	153	158	163	168	174	179	184
61	100	106	111	116	122	127	132	137	143	148	153	158	164	169	174	180	185	190
62	104	109	115	120	126	131	136	142	147	153	158	164	169	175	180	186	191	196
63	107	113	118	124	130	135	141	146	152	158	163	169	175	180	186	191	197	203
64	110	116	122	128	134	140	145	151	157	163	169	174	180	186	192	197	204	209
65	114	120	126	132	138	144	150	156	162	168	174	180	186	192	198	204	210	216
66	118	124	130	136	142	148	155	161	167	173	179	186	192	198	204	210	216	223
67	121	127	134	140	146	153	159	166	172	178	185	191	198	204	211	217	223	230
68	125	131	138	144	151	158	164	171	177	184	190	197	203	210	216	223	230	236
69	128	135	142	149	155	162	169	176	182	189	196	203	209	216	223	230	236	243
70	132	139	146	153	160	167	174	181	188	195	202	209	216	222	229	236	243	250
71	136	143	150	157	165	172	179	186	193	200	208	215	222	229	236	243	250	257
72	140	147	154	162	169	177	184	191	199	206	213	221	228	235	242	250	258	265
73	144	151	159	166	174	182	189	197	204	212	219	227	235	242	250	257	265	272
74	148	155	163	171	179	186	194	202	210	218	225	233	241	249	256	264	272	280
75	152	160	168	176	184	192	200	208	216	224	232	240	248	256	264	272	279	287
76	156	164	172	180	189	197	205	213	221	230	238	246	254	263	271	279	287	295

BMI greater than 35? Go to Table 2

Body Mass Index Table 2
BMI	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54
Height (inches)	Body Weight (pounds)
58	177	181	186	191	196	201	205	210	215	220	224	229	234	239	244	248	253	258
59	183	188	193	198	203	208	212	217	222	227	232	237	242	247	252	257	262	267
60	189	194	199	204	209	215	220	225	230	235	240	245	250	255	261	266	271	276
61	195	201	206	211	217	222	227	232	238	243	248	254	259	264	269	275	280	285
62	202	207	213	218	224	229	235	240	246	251	256	262	267	273	278	284	289	295
63	208	214	220	225	231	237	242	248	254	259	265	270	278	282	287	293	299	304
64	215	221	227	232	238	244	250	256	262	267	273	279	285	291	296	302	308	314
65	222	228	234	240	246	252	258	264	270	276	282	288	294	300	306	312	318	324
66	229	235	241	247	253	260	266	272	278	284	291	297	303	309	315	322	328	334
67	236	242	249	255	261	268	274	280	287	293	299	306	312	319	325	331	338	344
68	243	249	256	262	269	276	282	289	295	302	308	315	322	328	335	341	348	354
69	250	257	263	270	277	284	291	297	304	311	318	324	331	338	345	351	358	365
70	257	264	271	278	285	292	299	306	313	320	327	334	341	348	355	362	369	376
71	265	272	279	286	293	301	308	315	322	329	338	343	351	358	365	372	379	386
72	272	279	287	294	302	309	316	324	331	338	346	353	361	368	375	383	390	397
73	280	288	295	302	310	318	325	333	340	348	355	363	371	378	386	393	401	408
74	287	295	303	311	319	326	334	342	350	358	365	373	381	389	396	404	412	420
75	295	303	311	319	327	335	343	351	359	367	375	383	391	399	407	415	423	431
76	304	312	320	328	336	344	353	361	369	377	385	394	402	410	418	426	435	443

[Overweight Men At Risk Of Osteoarthritis Of Both Hip And Knee, ScienceDaily, May 29, 2008] —

Men who are overweight or obese are much more likely need a hip replacement for osteoarthritis than men who are of normal weight, finds new research.

People who are overweight are known to be more likely to get osteoarthritis of the knee, but this is the first study to show that being overweight is a risk factor for hip osteoarthritis in men but not women.

Researchers compared the body mass indexes of 1,473 Icelandic people who had undergone hip or knee replacement with those of 1,103 people who had not had joint replacement surgery. All were born between 1910 and 1939.

They found women who were overweight (BMI>25) were no more likely to have had a hip replacement than women of normal weight, but men were. Men who were obese (BMI>30) were 70 per cent more likely to have had hip replacement surgery.

People of both sexes who were overweight were much more likely to have had knee replacement surgery and the more overweight they were the more likely it was. Men who were obese were five times more likely to have had a replacement knee and women four times more likely.

The authors say: “The study supports a positive association between high BMI and total knee replacement in both sexes, but for total hip replacement the association with BMI seems to be weaker, and possibly negligible for women.”Journal reference:

Franklin et al. Sex differences in the association between body mass index and total hip or knee joint replacement due to osteoarthritis. Annals of the Rheumatic Diseases, 2008; DOI: 10.1136/ard.2007.086868